GPG2(1) GNU Privacy Guard 2.2 GPG2(1)

NAME

gpg2 - OpenPGP encryption and signing tool

SYNOPSIS

gpg2 [--homedir dir] [--options file] [options] command [args]

DESCRIPTION

gpg2 is the OpenPGP part of the GNU Privacy Guard (GnuPG). It is a
tool to provide digital encryption and signing services using the
OpenPGP standard. gpg2 features complete key management and all the
bells and whistles you would expect from a full OpenPGP
implementation.

There are two main versions of GnuPG: GnuPG 1.x and GnuPG 2.x. GnuPG
2.x supports modern encryption algorithms and thus should be
preferred over GnuPG 1.x. You only need to use GnuPG 1.x if your
platform doesn't support GnuPG 2.x, or you need support for some
features that GnuPG 2.x has deprecated, e.g., decrypting data created
with PGP-2 keys.

In contrast to the standalone command gpg from GnuPG 1.x, the 2.x
version is commonly installed under the name gpg2.

RETURN VALUE

The program returns 0 if there are no severe errors, 1 if at least a
signature was bad, and other error codes for fatal errors.

Note that signature verification requires exact knowledge of what has
been signed and by whom it has been signed. Using only the return
code is thus not an appropriate way to verify a signature by a
script. Either make proper use or the status codes or use the gpgv
tool which has been designed to make signature verification easy for
scripts.

WARNINGS

Use a good password for your user account and make sure that all
security issues are always fixed on your machine. Also employ
diligent physical protection to your machine. Consider to use a good
passphrase as a last resort protection to your secret key in the case
your machine gets stolen. It is important that your secret key is
never leaked. Using an easy to carry around token or smartcard with
the secret key is often a advisable.

If you are going to verify detached signatures, make sure that the
program knows about it; either give both filenames on the command
line or use `-' to specify STDIN.

For scripted or other unattended use of gpg make sure to use the
machine-parseable interface and not the default interface which is
intended for direct use by humans. The machine-parseable interface
provides a stable and well documented API independent of the locale
or future changes of gpg. To enable this interface use the options
--with-colons and --status-fd. For certain operations the option
--command-fd may come handy too. See this man page and the file
`DETAILS' for the specification of the interface. Note that the
GnuPG ``info'' pages as well as the PDF version of the GnuPG manual
features a chapter on unattended use of GnuPG. As an alternative the
library GPGME can be used as a high-level abstraction on top of that
interface.

INTEROPERABILITY

GnuPG tries to be a very flexible implementation of the OpenPGP
standard. In particular, GnuPG implements many of the optional parts
of the standard, such as the SHA-512 hash, and the ZLIB and BZIP2
compression algorithms. It is important to be aware that not all
OpenPGP programs implement these optional algorithms and that by
forcing their use via the --cipher-algo, --digest-algo,
--cert-digest-algo, or --compress-algo options in GnuPG, it is
possible to create a perfectly valid OpenPGP message, but one that
cannot be read by the intended recipient.

There are dozens of variations of OpenPGP programs available, and
each supports a slightly different subset of these optional
algorithms. For example, until recently, no (unhacked) version of
PGP supported the BLOWFISH cipher algorithm. A message using BLOWFISH
simply could not be read by a PGP user. By default, GnuPG uses the
standard OpenPGP preferences system that will always do the right
thing and create messages that are usable by all recipients,
regardless of which OpenPGP program they use. Only override this safe
default if you really know what you are doing.

If you absolutely must override the safe default, or if the
preferences on a given key are invalid for some reason, you are far
better off using the --pgp6, --pgp7, or --pgp8 options. These options
are safe as they do not force any particular algorithms in violation
of OpenPGP, but rather reduce the available algorithms to a "PGP-
safe" list.

COMMANDS

Commands are not distinguished from options except for the fact that
only one command is allowed. Generally speaking, irrelevant options
are silently ignored, and may not be checked for correctness.

gpg2 may be run with no commands. In this case it will print a
warning perform a reasonable action depending on the type of file it
is given as input (an encrypted message is decrypted, a signature is
verified, a file containing keys is listed, etc.).

If you run into any problems, please add the option --verbose to the
invocation to see more diagnostics.

Commands not specific to the function

--version
Print the program version and licensing information. Note
that you cannot abbreviate this command.


--help
-h Print a usage message summarizing the most useful command-line
options. Note that you cannot arbitrarily abbreviate this
command (though you can use its short form -h).


--warranty
Print warranty information.


--dump-options
Print a list of all available options and commands. Note that
you cannot abbreviate this command.

Commands to select the type of operation

--sign
-s Sign a message. This command may be combined with --encrypt
(to sign and encrypt a message), --symmetric (to sign and
symmetrically encrypt a message), or both --encrypt and
--symmetric (to sign and encrypt a message that can be
decrypted using a secret key or a passphrase). The signing
key is chosen by default or can be set explicitly using the
--local-user and --default-key options.


--clear-sign
--clearsign
Make a cleartext signature. The content in a cleartext
signature is readable without any special software. OpenPGP
software is only needed to verify the signature. cleartext
signatures may modify end-of-line whitespace for platform
independence and are not intended to be reversible. The
signing key is chosen by default or can be set explicitly
using the --local-user and --default-key options.


--detach-sign
-b Make a detached signature.


--encrypt
-e Encrypt data to one or more public keys. This command may be
combined with --sign (to sign and encrypt a message),
--symmetric (to encrypt a message that can be decrypted using
a secret key or a passphrase), or --sign and --symmetric
together (for a signed message that can be decrypted using a
secret key or a passphrase). --recipient and related options
specify which public keys to use for encryption.


--symmetric
-c Encrypt with a symmetric cipher using a passphrase. The
default symmetric cipher used is AES-128, but may be chosen
with the --cipher-algo option. This command may be combined
with --sign (for a signed and symmetrically encrypted
message), --encrypt (for a message that may be decrypted via a
secret key or a passphrase), or --sign and --encrypt together
(for a signed message that may be decrypted via a secret key
or a passphrase). gpg2 caches the passphrase used for
symmetric encryption so that a decrypt operation may not
require that the user needs to enter the passphrase. The
option --no-symkey-cache can be used to disable this feature.


--store
Store only (make a simple literal data packet).


--decrypt
-d Decrypt the file given on the command line (or STDIN if no
file is specified) and write it to STDOUT (or the file
specified with --output). If the decrypted file is signed, the
signature is also verified. This command differs from the
default operation, as it never writes to the filename which is
included in the file and it rejects files that don't begin
with an encrypted message.


--verify
Assume that the first argument is a signed file and verify it
without generating any output. With no arguments, the
signature packet is read from STDIN. If only one argument is
given, the specified file is expected to include a complete
signature.

With more than one argument, the first argument should specify
a file with a detached signature and the remaining files
should contain the signed data. To read the signed data from
STDIN, use `-' as the second filename. For security reasons,
a detached signature will not read the signed material from
STDIN if not explicitly specified.

Note: If the option --batch is not used, gpg2 may assume that
a single argument is a file with a detached signature, and it
will try to find a matching data file by stripping certain
suffixes. Using this historical feature to verify a detached
signature is strongly discouraged; you should always specify
the data file explicitly.

Note: When verifying a cleartext signature, gpg2 verifies only
what makes up the cleartext signed data and not any extra data
outside of the cleartext signature or the header lines
directly following the dash marker line. The option --output
may be used to write out the actual signed data, but there are
other pitfalls with this format as well. It is suggested to
avoid cleartext signatures in favor of detached signatures.

Note: Sometimes the use of the gpgv tool is easier than using
the full-fledged gpg with this option. gpgv is designed to
compare signed data against a list of trusted keys and returns
with success only for a good signature. It has its own manual
page.


--multifile
This modifies certain other commands to accept multiple files
for processing on the command line or read from STDIN with
each filename on a separate line. This allows for many files
to be processed at once. --multifile may currently be used
along with --verify, --encrypt, and --decrypt. Note that
--multifile --verify may not be used with detached signatures.


--verify-files
Identical to --multifile --verify.


--encrypt-files
Identical to --multifile --encrypt.


--decrypt-files
Identical to --multifile --decrypt.


--list-keys
-k
--list-public-keys
List the specified keys. If no keys are specified, then all
keys from the configured public keyrings are listed.

Never use the output of this command in scripts or other
programs. The output is intended only for humans and its
format is likely to change. The --with-colons option emits
the output in a stable, machine-parseable format, which is
intended for use by scripts and other programs.


--list-secret-keys
-K List the specified secret keys. If no keys are specified,
then all known secret keys are listed. A # after the initial
tags sec or ssb means that the secret key or subkey is
currently not usable. We also say that this key has been
taken offline (for example, a primary key can be taken offline
by exporting the key using the command
--export-secret-subkeys). A > after these tags indicate that
the key is stored on a smartcard. See also --list-keys.


--check-signatures
--check-sigs
Same as --list-keys, but the key signatures are verified and
listed too. Note that for performance reasons the revocation
status of a signing key is not shown. This command has the
same effect as using --list-keys with --with-sig-check.

The status of the verification is indicated by a flag directly
following the "sig" tag (and thus before the flags described
below. A "!" indicates that the signature has been
successfully verified, a "-" denotes a bad signature and a "%"
is used if an error occurred while checking the signature
(e.g. a non supported algorithm). Signatures where the public
key is not available are not listed; to see their keyids the
command --list-sigs can be used.

For each signature listed, there are several flags in between
the signature status flag and keyid. These flags give
additional information about each key signature. From left to
right, they are the numbers 1-3 for certificate check level
(see --ask-cert-level), "L" for a local or non-exportable
signature (see --lsign-key), "R" for a nonRevocable signature
(see the --edit-key command "nrsign"), "P" for a signature
that contains a policy URL (see --cert-policy-url), "N" for a
signature that contains a notation (see --cert-notation), "X"
for an eXpired signature (see --ask-cert-expire), and the
numbers 1-9 or "T" for 10 and above to indicate trust
signature levels (see the --edit-key command "tsign").


--locate-keys
--locate-external-keys
Locate the keys given as arguments. This command basically
uses the same algorithm as used when locating keys for
encryption and may thus be used to see what keys gpg2 might
use. In particular external methods as defined by
--auto-key-locate are used to locate a key if the arguments
comain valid mail addresses. Only public keys are listed.

The variant --locate-external-keys does not consider a locally
existing key and can thus be used to force the refresh of a
key via the defined external methods. If a fingerprint is
given and and the methods defined by --auto-key-locate define
LDAP servers, the key is fetched from these resources; defined
non-LDAP keyservers are skipped.


--show-keys
This commands takes OpenPGP keys as input and prints
information about them in the same way the command --list-keys
does for locally stored key. In addition the list options
show-unusable-uids, show-unusable-subkeys, show-notations and
show-policy-urls are also enabled. As usual for automated
processing, this command should be combined with the option
--with-colons.


--fingerprint
List all keys (or the specified ones) along with their
fingerprints. This is the same output as --list-keys but with
the additional output of a line with the fingerprint. May also
be combined with --check-signatures. If this command is given
twice, the fingerprints of all secondary keys are listed too.
This command also forces pretty printing of fingerprints if
the keyid format has been set to "none".


--list-packets
List only the sequence of packets. This command is only
useful for debugging. When used with option --verbose the
actual MPI values are dumped and not only their lengths. Note
that the output of this command may change with new releases.


--edit-card
--card-edit
Present a menu to work with a smartcard. The subcommand "help"
provides an overview on available commands. For a detailed
description, please see the Card HOWTO at
https://gnupg.org/documentation/howtos.html#GnuPG-cardHOWTO .


--card-status
Show the content of the smart card.


--change-pin
Present a menu to allow changing the PIN of a smartcard. This
functionality is also available as the subcommand "passwd"
with the --edit-card command.


--delete-keys name
Remove key from the public keyring. In batch mode either --yes
is required or the key must be specified by fingerprint. This
is a safeguard against accidental deletion of multiple keys.
If the exclamation mark syntax is used with the fingerprint of
a subkey only that subkey is deleted; if the exclamation mark
is used with the fingerprint of the primary key the entire
public key is deleted.


--delete-secret-keys name
Remove key from the secret keyring. In batch mode the key must
be specified by fingerprint. The option --yes can be used to
advise gpg-agent not to request a confirmation. This extra
pre-caution is done because gpg2 can't be sure that the secret
key (as controlled by gpg-agent) is only used for the given
OpenPGP public key. If the exclamation mark syntax is used
with the fingerprint of a subkey only the secret part of that
subkey is deleted; if the exclamation mark is used with the
fingerprint of the primary key only the secret part of the
primary key is deleted.


--delete-secret-and-public-key name
Same as --delete-key, but if a secret key exists, it will be
removed first. In batch mode the key must be specified by
fingerprint. The option --yes can be used to advise gpg-agent
not to request a confirmation.


--export
Either export all keys from all keyrings (default keyring and
those registered via option --keyring), or if at least one
name is given, those of the given name. The exported keys are
written to STDOUT or to the file given with option --output.
Use together with --armor to mail those keys.


--send-keys keyIDs
Similar to --export but sends the keys to a keyserver.
Fingerprints may be used instead of key IDs. Don't send your
complete keyring to a keyserver --- select only those keys
which are new or changed by you. If no keyIDs are given, gpg2
does nothing.

Take care: Keyservers are by design write only systems and
thus it is not possible to ever delete keys once they have
been send to a keyserver.


--export-secret-keys
--export-secret-subkeys
Same as --export, but exports the secret keys instead. The
exported keys are written to STDOUT or to the file given with
option --output. This command is often used along with the
option --armor to allow for easy printing of the key for paper
backup; however the external tool paperkey does a better job
of creating backups on paper. Note that exporting a secret
key can be a security risk if the exported keys are sent over
an insecure channel.

The second form of the command has the special property to
render the secret part of the primary key useless; this is a
GNU extension to OpenPGP and other implementations can not be
expected to successfully import such a key. Its intended use
is in generating a full key with an additional signing subkey
on a dedicated machine. This command then exports the key
without the primary key to the main machine.

GnuPG may ask you to enter the passphrase for the key. This
is required, because the internal protection method of the
secret key is different from the one specified by the OpenPGP
protocol.


--export-ssh-key
This command is used to export a key in the OpenSSH public key
format. It requires the specification of one key by the usual
means and exports the latest valid subkey which has an
authentication capability to STDOUT or to the file given with
option --output. That output can directly be added to ssh's
`authorized_key' file.

By specifying the key to export using a key ID or a
fingerprint suffixed with an exclamation mark (!), a specific
subkey or the primary key can be exported. This does not even
require that the key has the authentication capability flag
set.


--import
--fast-import
Import/merge keys. This adds the given keys to the keyring.
The fast version is currently just a synonym.

There are a few other options which control how this command
works. Most notable here is the --import-options merge-only
option which does not insert new keys but does only the
merging of new signatures, user-IDs and subkeys.


--receive-keys keyIDs
--recv-keys keyIDs
Import the keys with the given keyIDs from a keyserver.


--refresh-keys
Request updates from a keyserver for keys that already exist
on the local keyring. This is useful for updating a key with
the latest signatures, user IDs, etc. Calling this with no
arguments will refresh the entire keyring.


--search-keys names
Search the keyserver for the given names. Multiple names given
here will be joined together to create the search string for
the keyserver. Note that keyservers search for names in a
different and simpler way than gpg does. The best choice is
to use a mail address. Due to data privacy reasons keyservers
may even not even allow searching by user id or mail address
and thus may only return results when being used with the
--recv-key command to search by key fingerprint or keyid.


--fetch-keys URIs
Retrieve keys located at the specified URIs. Note that
different installations of GnuPG may support different
protocols (HTTP, FTP, LDAP, etc.). When using HTTPS the
system provided root certificates are used by this command.


--update-trustdb
Do trust database maintenance. This command iterates over all
keys and builds the Web of Trust. This is an interactive
command because it may have to ask for the "ownertrust" values
for keys. The user has to give an estimation of how far she
trusts the owner of the displayed key to correctly certify
(sign) other keys. GnuPG only asks for the ownertrust value if
it has not yet been assigned to a key. Using the --edit-key
menu, the assigned value can be changed at any time.


--check-trustdb
Do trust database maintenance without user interaction. From
time to time the trust database must be updated so that
expired keys or signatures and the resulting changes in the
Web of Trust can be tracked. Normally, GnuPG will calculate
when this is required and do it automatically unless
--no-auto-check-trustdb is set. This command can be used to
force a trust database check at any time. The processing is
identical to that of --update-trustdb but it skips keys with a
not yet defined "ownertrust".

For use with cron jobs, this command can be used together with
--batch in which case the trust database check is done only if
a check is needed. To force a run even in batch mode add the
option --yes.


--export-ownertrust
Send the ownertrust values to STDOUT. This is useful for
backup purposes as these values are the only ones which can't
be re-created from a corrupted trustdb. Example:
gpg2 --export-ownertrust > otrust.txt


--import-ownertrust
Update the trustdb with the ownertrust values stored in files
(or STDIN if not given); existing values will be overwritten.
In case of a severely damaged trustdb and if you have a recent
backup of the ownertrust values (e.g. in the file
`otrust.txt'), you may re-create the trustdb using these
commands:
cd ~/.gnupg
rm trustdb.gpg
gpg2 --import-ownertrust < otrust.txt


--rebuild-keydb-caches
When updating from version 1.0.6 to 1.0.7 this command should
be used to create signature caches in the keyring. It might be
handy in other situations too.


--print-md algo
--print-mds
Print message digest of algorithm algo for all given files or
STDIN. With the second form (or a deprecated "*" for algo)
digests for all available algorithms are printed.


--gen-random 0|1|2|16|30 count
Emit count random bytes of the given quality level 0, 1 or 2.
If count is not given or zero, an endless sequence of random
bytes will be emitted. If used with --armor the output will
be base64 encoded. The special level 16 uses a quality level
of 1 and outputs and endless stream of hex-encoded octets.
The special level 30 outputs random as 30 zBase-32 characters.


--gen-prime mode bits
Use the source, Luke :-). The output format is subject to
change with ant release.


--enarmor
--dearmor
Pack or unpack an arbitrary input into/from an OpenPGP ASCII
armor. This is a GnuPG extension to OpenPGP and in general
not very useful.


--tofu-policy {auto|good|unknown|bad|ask} keys
Set the TOFU policy for all the bindings associated with the
specified keys. For more information about the meaning of the
policies, see: [trust-model-tofu]. The keys may be specified
either by their fingerprint (preferred) or their keyid.

How to manage your keys

This section explains the main commands for key management.


--quick-generate-key user-id [algo [usage [expire]]]
--quick-gen-key
This is a simple command to generate a standard key with one
user id. In contrast to --generate-key the key is generated
directly without the need to answer a bunch of prompts.
Unless the option --yes is given, the key creation will be
canceled if the given user id already exists in the keyring.

If invoked directly on the console without any special options
an answer to a ``Continue?'' style confirmation prompt is
required. In case the user id already exists in the keyring a
second prompt to force the creation of the key will show up.

If algo or usage are given, only the primary key is created
and no prompts are shown. To specify an expiration date but
still create a primary and subkey use ``default'' or ``future-
default'' for algo and ``default'' for usage. For a
description of these optional arguments see the command
--quick-add-key. The usage accepts also the value ``cert''
which can be used to create a certification only primary key;
the default is to a create certification and signing key.

The expire argument can be used to specify an expiration date
for the key. Several formats are supported; commonly the ISO
formats ``YYYY-MM-DD'' or ``YYYYMMDDThhmmss'' are used. To
make the key expire in N seconds, N days, N weeks, N months,
or N years use ``seconds=N'', ``Nd'', ``Nw'', ``Nm'', or
``Ny'' respectively. Not specifying a value, or using ``-''
results in a key expiring in a reasonable default interval.
The values ``never'', ``none'' can be used for no expiration
date.

If this command is used with --batch, --pinentry-mode has been
set to loopback, and one of the passphrase options
(--passphrase, --passphrase-fd, or --passphrase-file) is used,
the supplied passphrase is used for the new key and the agent
does not ask for it. To create a key without any protection
--passphrase '' may be used.

To create an OpenPGP key from the keys available on the
currently inserted smartcard, the special string ``card'' can
be used for algo. If the card features an encryption and a
signing key, gpg will figure them out and creates an OpenPGP
key consisting of the usual primary key and one subkey. This
works only with certain smartcards. Note that the interactive
--full-gen-key command allows to do the same but with greater
flexibility in the selection of the smartcard keys.

Note that it is possible to create a primary key and a subkey
using non-default algorithms by using ``default'' and changing
the default parameters using the option
--default-new-key-algo.


--quick-set-expire fpr expire [*|subfprs]
With two arguments given, directly set the expiration time of
the primary key identified by fpr to expire. To remove the
expiration time 0 can be used. With three arguments and the
third given as an asterisk, the expiration time of all non-
revoked and not yet expired subkeys are set to expire. With
more than two arguments and a list of fingerprints given for
subfprs, all non-revoked subkeys matching these fingerprints
are set to expire.


--quick-add-key fpr [algo [usage [expire]]]
Directly add a subkey to the key identified by the fingerprint
fpr. Without the optional arguments an encryption subkey is
added. If any of the arguments are given a more specific
subkey is added.

algo may be any of the supported algorithms or curve names
given in the format as used by key listings. To use the
default algorithm the string ``default'' or ``-'' can be used.
Supported algorithms are ``rsa'', ``dsa'', ``elg'',
``ed25519'', ``cv25519'', and other ECC curves. For example
the string ``rsa'' adds an RSA key with the default key
length; a string ``rsa4096'' requests that the key length is
4096 bits. The string ``future-default'' is an alias for the
algorithm which will likely be used as default algorithm in
future versions of gpg. To list the supported ECC curves the
command gpg --with-colons --list-config curve can be used.

Depending on the given algo the subkey may either be an
encryption subkey or a signing subkey. If an algorithm is
capable of signing and encryption and such a subkey is
desired, a usage string must be given. This string is either
``default'' or ``-'' to keep the default or a comma delimited
list (or space delimited list) of keywords: ``sign'' for a
signing subkey, ``auth'' for an authentication subkey, and
``encr'' for an encryption subkey (``encrypt'' can be used as
alias for ``encr''). The valid combinations depend on the
algorithm.

The expire argument can be used to specify an expiration date
for the key. Several formats are supported; commonly the ISO
formats ``YYYY-MM-DD'' or ``YYYYMMDDThhmmss'' are used. To
make the key expire in N seconds, N days, N weeks, N months,
or N years use ``seconds=N'', ``Nd'', ``Nw'', ``Nm'', or
``Ny'' respectively. Not specifying a value, or using ``-''
results in a key expiring in a reasonable default interval.
The values ``never'', ``none'' can be used for no expiration
date.


--generate-key
--gen-key
Generate a new key pair using the current default parameters.
This is the standard command to create a new key. In addition
to the key a revocation certificate is created and stored in
the `openpgp-revocs.d' directory below the GnuPG home
directory.


--full-generate-key
--full-gen-key
Generate a new key pair with dialogs for all options. This is
an extended version of --generate-key.

There is also a feature which allows you to create keys in
batch mode. See the manual section ``Unattended key
generation'' on how to use this.


--generate-revocation name
--gen-revoke name
Generate a revocation certificate for the complete key. To
only revoke a subkey or a key signature, use the --edit
command.

This command merely creates the revocation certificate so that
it can be used to revoke the key if that is ever needed. To
actually revoke a key the created revocation certificate needs
to be merged with the key to revoke. This is done by
importing the revocation certificate using the --import
command. Then the revoked key needs to be published, which is
best done by sending the key to a keyserver (command
--send-key) and by exporting (--export) it to a file which is
then send to frequent communication partners.


--generate-designated-revocation name
--desig-revoke name
Generate a designated revocation certificate for a key. This
allows a user (with the permission of the keyholder) to revoke
someone else's key.


--edit-key
Present a menu which enables you to do most of the key
management related tasks. It expects the specification of a
key on the command line.


uid n Toggle selection of user ID or photographic user ID
with index n. Use * to select all and 0 to deselect
all.


key n Toggle selection of subkey with index n or key ID n.
Use * to select all and 0 to deselect all.


sign Make a signature on key of user name. If the key is not
yet signed by the default user (or the users given with
-u), the program displays the information of the key
again, together with its fingerprint and asks whether
it should be signed. This question is repeated for all
users specified with -u.


lsign Same as "sign" but the signature is marked as non-
exportable and will therefore never be used by others.
This may be used to make keys valid only in the local
environment.


nrsign Same as "sign" but the signature is marked as non-
revocable and can therefore never be revoked.


tsign Make a trust signature. This is a signature that
combines the notions of certification (like a regular
signature), and trust (like the "trust" command). It is
generally useful in distinct communities or groups to
implement the concept of a Trusted Introducer. For
more information please read the sections ``Trust
Signature'' and ``Regular Expression'' in RFC-4880.

Note that "l" (for local / non-exportable), "nr" (for non-
revocable, and "t" (for trust) may be freely mixed and
prefixed to "sign" to create a signature of any type desired.

If the option --only-sign-text-ids is specified, then any non-text
based user ids (e.g., photo IDs) will not be selected for signing.


delsig Delete a signature. Note that it is not possible to
retract a signature, once it has been send to the
public (i.e. to a keyserver). In that case you better
use revsig.


revsig Revoke a signature. For every signature which has been
generated by one of the secret keys, GnuPG asks whether
a revocation certificate should be generated.


check Check the signatures on all selected user IDs. With
the extra option selfsig only self-signatures are
shown.


adduid Create an additional user ID.


addphoto
Create a photographic user ID. This will prompt for a
JPEG file that will be embedded into the user ID. Note
that a very large JPEG will make for a very large key.
Also note that some programs will display your JPEG
unchanged (GnuPG), and some programs will scale it to
fit in a dialog box (PGP).


showphoto
Display the selected photographic user ID.


deluid Delete a user ID or photographic user ID. Note that it
is not possible to retract a user id, once it has been
send to the public (i.e. to a keyserver). In that case
you better use revuid.


revuid Revoke a user ID or photographic user ID.


primary
Flag the current user id as the primary one, removes
the primary user id flag from all other user ids and
sets the timestamp of all affected self-signatures one
second ahead. Note that setting a photo user ID as
primary makes it primary over other photo user IDs, and
setting a regular user ID as primary makes it primary
over other regular user IDs.


keyserver
Set a preferred keyserver for the specified user ID(s).
This allows other users to know where you prefer they
get your key from. See --keyserver-options
honor-keyserver-url for more on how this works.
Setting a value of "none" removes an existing preferred
keyserver.


notation
Set a name=value notation for the specified user ID(s).
See --cert-notation for more on how this works. Setting
a value of "none" removes all notations, setting a
notation prefixed with a minus sign (-) removes that
notation, and setting a notation name (without the
=value) prefixed with a minus sign removes all
notations with that name.


pref List preferences from the selected user ID. This shows
the actual preferences, without including any implied
preferences.


showpref
More verbose preferences listing for the selected user
ID. This shows the preferences in effect by including
the implied preferences of 3DES (cipher), SHA-1
(digest), and Uncompressed (compression) if they are
not already included in the preference list. In
addition, the preferred keyserver and signature
notations (if any) are shown.


setpref string
Set the list of user ID preferences to string for all
(or just the selected) user IDs. Calling setpref with
no arguments sets the preference list to the default
(either built-in or set via --default-preference-list),
and calling setpref with "none" as the argument sets an
empty preference list. Use gpg2 --version to get a list
of available algorithms. Note that while you can change
the preferences on an attribute user ID (aka "photo
ID"), GnuPG does not select keys via attribute user IDs
so these preferences will not be used by GnuPG. Note
that an unattended version of this command is available
as --quick-update-pref.

When setting preferences, you should list the
algorithms in the order which you'd like to see them
used by someone else when encrypting a message to your
key. If you don't include 3DES, it will be
automatically added at the end. Note that there are
many factors that go into choosing an algorithm (for
example, your key may not be the only recipient), and
so the remote OpenPGP application being used to send to
you may or may not follow your exact chosen order for a
given message. It will, however, only choose an
algorithm that is present on the preference list of
every recipient key. See also the INTEROPERABILITY
WITH OTHER OPENPGP PROGRAMS section below.


addkey Add a subkey to this key.


addcardkey
Generate a subkey on a card and add it to this key.


keytocard
Transfer the selected secret subkey (or the primary key
if no subkey has been selected) to a smartcard. The
secret key in the keyring will be replaced by a stub if
the key could be stored successfully on the card and
you use the save command later. Only certain key types
may be transferred to the card. A sub menu allows you
to select on what card to store the key. Note that it
is not possible to get that key back from the card - if
the card gets broken your secret key will be lost
unless you have a backup somewhere.


bkuptocard file
Restore the given file to a card. This command may be
used to restore a backup key (as generated during card
initialization) to a new card. In almost all cases this
will be the encryption key. You should use this command
only with the corresponding public key and make sure
that the file given as argument is indeed the backup to
restore. You should then select 2 to restore as
encryption key. You will first be asked to enter the
passphrase of the backup key and then for the Admin PIN
of the card.


delkey Remove a subkey (secondary key). Note that it is not
possible to retract a subkey, once it has been send to
the public (i.e. to a keyserver). In that case you
better use revkey. Also note that this only deletes
the public part of a key.


revkey Revoke a subkey.


expire Change the key or subkey expiration time. If a subkey
is selected, the expiration time of this subkey will be
changed. With no selection, the key expiration of the
primary key is changed.


trust Change the owner trust value for the key. This updates
the trust-db immediately and no save is required.


disable
enable Disable or enable an entire key. A disabled key can not
normally be used for encryption.


addrevoker
Add a designated revoker to the key. This takes one
optional argument: "sensitive". If a designated revoker
is marked as sensitive, it will not be exported by
default (see export-options).


passwd Change the passphrase of the secret key.


toggle This is dummy command which exists only for backward
compatibility.


clean Compact (by removing all signatures except the selfsig)
any user ID that is no longer usable (e.g. revoked, or
expired). Then, remove any signatures that are not
usable by the trust calculations. Specifically, this
removes any signature that does not validate, any
signature that is superseded by a later signature,
revoked signatures, and signatures issued by keys that
are not present on the keyring.


minimize
Make the key as small as possible. This removes all
signatures from each user ID except for the most recent
self-signature.


change-usage
Change the usage flags (capabilities) of the primary
key or of subkeys. These usage flags (e.g. Certify,
Sign, Authenticate, Encrypt) are set during key
creation. Sometimes it is useful to have the
opportunity to change them (for example to add
Authenticate) after they have been created. Please
take care when doing this; the allowed usage flags
depend on the key algorithm.


cross-certify
Add cross-certification signatures to signing subkeys
that may not currently have them. Cross-certification
signatures protect against a subtle attack against
signing subkeys. See --require-cross-certification.
All new keys generated have this signature by default,
so this command is only useful to bring older keys up
to date.


save Save all changes to the keyring and quit.


quit Quit the program without updating the keyring.

The listing shows you the key with its secondary keys and all
user IDs. The primary user ID is indicated by a dot, and
selected keys or user IDs are indicated by an asterisk. The
trust value is displayed with the primary key: "trust" is the
assigned owner trust and "validity" is the calculated validity
of the key. Validity values are also displayed for all user
IDs. For possible values of trust, see: [trust-values].


--sign-key name
Signs a public key with your secret key. This is a shortcut
version of the subcommand "sign" from --edit.


--lsign-key name
Signs a public key with your secret key but marks it as non-
exportable. This is a shortcut version of the subcommand
"lsign" from --edit-key.


--quick-sign-key fpr [names]
--quick-lsign-key fpr [names]
Directly sign a key from the passphrase without any further
user interaction. The fpr must be the verified primary
fingerprint of a key in the local keyring. If no names are
given, all useful user ids are signed; with given [names] only
useful user ids matching one of theses names are signed. By
default, or if a name is prefixed with a '*', a case
insensitive substring match is used. If a name is prefixed
with a '=' a case sensitive exact match is done.

The command --quick-lsign-key marks the signatures as non-
exportable. If such a non-exportable signature already exists
the --quick-sign-key turns it into a exportable signature. If
you need to update an existing signature, for example to add
or change notation data, you need to use the option
--force-sign-key.

This command uses reasonable defaults and thus does not
provide the full flexibility of the "sign" subcommand from
--edit-key. Its intended use is to help unattended key
signing by utilizing a list of verified fingerprints.


--quick-add-uid user-id new-user-id
This command adds a new user id to an existing key. In
contrast to the interactive sub-command adduid of --edit-key
the new-user-id is added verbatim with only leading and
trailing white space removed, it is expected to be UTF-8
encoded, and no checks on its form are applied.


--quick-revoke-uid user-id user-id-to-revoke
This command revokes a user ID on an existing key. It cannot
be used to revoke the last user ID on key (some non-revoked
user ID must remain), with revocation reason ``User ID is no
longer valid''. If you want to specify a different revocation
reason, or to supply supplementary revocation text, you should
use the interactive sub-command revuid of --edit-key.


--quick-revoke-sig fpr signing-fpr [names]
This command revokes the key signatures made by signing-fpr
from the key specified by the fingerprint fpr. With names
given only the signatures on user ids of the key matching any
of the given names are affected (see --quick-sign-key). If a
revocation already exists a notice is printed instead of
creating a new revocation; no error is returned in this case.
Note that key signature revocations may be superseded by a
newer key signature and in turn again revoked.


--quick-set-primary-uid user-id primary-user-id
This command sets or updates the primary user ID flag on an
existing key. user-id specifies the key and primary-user-id
the user ID which shall be flagged as the primary user ID.
The primary user ID flag is removed from all other user ids
and the timestamp of all affected self-signatures is set one
second ahead.


--quick-update-pref user-id
This command updates the preference list of the key to the
current default value (either built-in or set via
--default-preference-list). This is the unattended version of
of using "setpref" in the --key-edit menu without giving a
list. Note that you can show the preferences in a key listing
by using --list-options show-pref or --list-options
show-pref-verbose. You should also re-distribute updated keys
to your peers.


--change-passphrase user-id
--passwd user-id
Change the passphrase of the secret key belonging to the
certificate specified as user-id. This is a shortcut for the
sub-command passwd of the edit key menu. When using together
with the option --dry-run this will not actually change the
passphrase but check that the current passphrase is correct.

OPTIONS

gpg2 features a bunch of options to control the exact behaviour and
to change the default configuration.


Long options can be put in an options file (default
"~/.gnupg/gpg.conf"). Short option names will not work - for example,
"armor" is a valid option for the options file, while "a" is not. Do
not write the 2 dashes, but simply the name of the option and any
required arguments. Lines with a hash ('#') as the first non-white-
space character are ignored. Commands may be put in this file too,
but that is not generally useful as the command will execute
automatically with every execution of gpg.

Please remember that option parsing stops as soon as a non-option is
encountered, you can explicitly stop parsing by using the special
option --.

How to change the configuration

These options are used to change the configuration and most of them
are usually found in the option file.


--default-key name
Use name as the default key to sign with. If this option is
not used, the default key is the first key found in the secret
keyring. Note that -u or --local-user overrides this option.
This option may be given multiple times. In this case, the
last key for which a secret key is available is used. If
there is no secret key available for any of the specified
values, GnuPG will not emit an error message but continue as
if this option wasn't given.


--default-recipient name
Use name as default recipient if option --recipient is not
used and don't ask if this is a valid one. name must be non-
empty.


--default-recipient-self
Use the default key as default recipient if option --recipient
is not used and don't ask if this is a valid one. The default
key is the first one from the secret keyring or the one set
with --default-key.


--no-default-recipient
Reset --default-recipient and --default-recipient-self.
Should not be used in an option file.


-v, --verbose
Give more information during processing. If used twice, the
input data is listed in detail.


--no-verbose
Reset verbose level to 0. Should not be used in an option
file.


-q, --quiet
Try to be as quiet as possible. Should not be used in an
option file.


--batch
--no-batch
Use batch mode. Never ask, do not allow interactive commands.
--no-batch disables this option. Note that even with a
filename given on the command line, gpg might still need to
read from STDIN (in particular if gpg figures that the input
is a detached signature and no data file has been specified).
Thus if you do not want to feed data via STDIN, you should
connect STDIN to `/dev/null'.

It is highly recommended to use this option along with the
options --status-fd and --with-colons for any unattended use
of gpg. Should not be used in an option file.


--no-tty
Make sure that the TTY (terminal) is never used for any
output. This option is needed in some cases because GnuPG
sometimes prints warnings to the TTY even if --batch is used.


--yes Assume "yes" on most questions. Should not be used in an
option file.


--no Assume "no" on most questions. Should not be used in an
option file.


--list-options parameters
This is a space or comma delimited string that gives options
used when listing keys and signatures (that is, --list-keys,
--check-signatures, --list-public-keys, --list-secret-keys,
and the --edit-key functions). Options can be prepended with
a no- (after the two dashes) to give the opposite meaning.
The options are:


show-photos
Causes --list-keys, --check-signatures,
--list-public-keys, and --list-secret-keys to display
any photo IDs attached to the key. Defaults to no. See
also --photo-viewer. Does not work with --with-colons:
see --attribute-fd for the appropriate way to get photo
data for scripts and other frontends.


show-usage
Show usage information for keys and subkeys in the
standard key listing. This is a list of letters
indicating the allowed usage for a key (E=encryption,
S=signing, C=certification, A=authentication).
Defaults to yes.


show-policy-urls
Show policy URLs in the --check-signatures listings.
Defaults to no.


show-notations
show-std-notations
show-user-notations
Show all, IETF standard, or user-defined signature
notations in the --check-signatures listings. Defaults
to no.


show-keyserver-urls
Show any preferred keyserver URL in the
--check-signatures listings. Defaults to no.


show-uid-validity
Display the calculated validity of user IDs during key
listings. Defaults to yes.


show-unusable-uids
Show revoked and expired user IDs in key listings.
Defaults to no.


show-unusable-subkeys
Show revoked and expired subkeys in key listings.
Defaults to no.


show-keyring
Display the keyring name at the head of key listings to
show which keyring a given key resides on. Defaults to
no.


show-sig-expire
Show signature expiration dates (if any) during
--check-signatures listings. Defaults to no.


show-sig-subpackets
Include signature subpackets in the key listing. This
option can take an optional argument list of the
subpackets to list. If no argument is passed, list all
subpackets. Defaults to no. This option is only
meaningful when using --with-colons along with
--check-signatures.


show-only-fpr-mbox
For each user-id which has a valid mail address print
only the fingerprint followed by the mail address.


--verify-options parameters
This is a space or comma delimited string that gives options
used when verifying signatures. Options can be prepended with
a `no-' to give the opposite meaning. The options are:


show-photos
Display any photo IDs present on the key that issued
the signature. Defaults to no. See also
--photo-viewer.


show-policy-urls
Show policy URLs in the signature being verified.
Defaults to yes.


show-notations
show-std-notations
show-user-notations
Show all, IETF standard, or user-defined signature
notations in the signature being verified. Defaults to
IETF standard.


show-keyserver-urls
Show any preferred keyserver URL in the signature being
verified. Defaults to yes.


show-uid-validity
Display the calculated validity of the user IDs on the
key that issued the signature. Defaults to yes.


show-unusable-uids
Show revoked and expired user IDs during signature
verification. Defaults to no.


show-primary-uid-only
Show only the primary user ID during signature
verification. That is all the AKA lines as well as
photo Ids are not shown with the signature verification
status.


pka-lookups
Enable PKA lookups to verify sender addresses. Note
that PKA is based on DNS, and so enabling this option
may disclose information on when and what signatures
are verified or to whom data is encrypted. This is
similar to the "web bug" described for the
--auto-key-retrieve option.


pka-trust-increase
Raise the trust in a signature to full if the signature
passes PKA validation. This option is only meaningful
if pka-lookups is set.


--enable-large-rsa
--disable-large-rsa
With --generate-key and --batch, enable the creation of RSA
secret keys as large as 8192 bit. Note: 8192 bit is more than
is generally recommended. These large keys don't
significantly improve security, but they are more expensive to
use, and their signatures and certifications are larger. This
option is only available if the binary was build with large-
secmem support.


--enable-dsa2
--disable-dsa2
Enable hash truncation for all DSA keys even for old DSA Keys
up to 1024 bit. This is also the default with --openpgp.
Note that older versions of GnuPG also required this flag to
allow the generation of DSA larger than 1024 bit.


--photo-viewer string
This is the command line that should be run to view a photo
ID. "%i" will be expanded to a filename containing the photo.
"%I" does the same, except the file will not be deleted once
the viewer exits. Other flags are "%k" for the key ID, "%K"
for the long key ID, "%f" for the key fingerprint, "%t" for
the extension of the image type (e.g. "jpg"), "%T" for the
MIME type of the image (e.g. "image/jpeg"), "%v" for the
single-character calculated validity of the image being viewed
(e.g. "f"), "%V" for the calculated validity as a string (e.g.
"full"), "%U" for a base32 encoded hash of the user ID, and
"%%" for an actual percent sign. If neither %i or %I are
present, then the photo will be supplied to the viewer on
standard input.

On Unix the default viewer is xloadimage -fork -quiet -title
'KeyID 0x%k' STDIN with a fallback to display -title 'KeyID
0x%k' %i and finally to xdg-open %i. On Windows !ShellExecute
400 %i is used; here the command is a meta command to use that
API call followed by a wait time in milliseconds which is used
to give the viewer time to read the temporary image file
before gpg deletes it again. Note that if your image viewer
program is not secure, then executing it from gpg does not
make it secure.


--exec-path string
Sets a list of directories to search for photo viewers If not
provided photo viewers use the PATH environment variable.


--keyring file
Add file to the current list of keyrings. If file begins with
a tilde and a slash, these are replaced by the $HOME
directory. If the filename does not contain a slash, it is
assumed to be in the GnuPG home directory ("~/.gnupg" unless
--homedir or $GNUPGHOME is used).

Note that this adds a keyring to the current list. If the
intent is to use the specified keyring alone, use --keyring
along with --no-default-keyring.

If the option --no-keyring has been used no keyrings will be
used at all.


--primary-keyring file
This is a varian of --keyring and designates file as the
primary public keyring. This means that newly imported keys
(via --import or keyserver --recv-from) will go to this
keyring.


--secret-keyring file
This is an obsolete option and ignored. All secret keys are
stored in the `private-keys-v1.d' directory below the GnuPG
home directory.


--trustdb-name file
Use file instead of the default trustdb. If file begins with a
tilde and a slash, these are replaced by the $HOME directory.
If the filename does not contain a slash, it is assumed to be
in the GnuPG home directory (`~/.gnupg' if --homedir or
$GNUPGHOME is not used).


--homedir dir
Set the name of the home directory to dir. If this option is
not used, the home directory defaults to `~/.gnupg'. It is
only recognized when given on the command line. It also
overrides any home directory stated through the environment
variable `GNUPGHOME' or (on Windows systems) by means of the
Registry entry HKCU\Software\GNU\GnuPG:HomeDir.

On Windows systems it is possible to install GnuPG as a
portable application. In this case only this command line
option is considered, all other ways to set a home directory
are ignored.

To install GnuPG as a portable application under Windows,
create an empty file named `gpgconf.ctl' in the same directory
as the tool `gpgconf.exe'. The root of the installation is
then that directory; or, if `gpgconf.exe' has been installed
directly below a directory named `bin', its parent directory.
You also need to make sure that the following directories
exist and are writable: `ROOT/home' for the GnuPG home and
`ROOT/usr/var/cache/gnupg' for internal cache files.


--display-charset name
Set the name of the native character set. This is used to
convert some informational strings like user IDs to the proper
UTF-8 encoding. Note that this has nothing to do with the
character set of data to be encrypted or signed; GnuPG does
not recode user-supplied data. If this option is not used, the
default character set is determined from the current locale. A
verbosity level of 3 shows the chosen set. This option should
not be used on Windows. Valid values for name are:


iso-8859-1
This is the Latin 1 set.


iso-8859-2
The Latin 2 set.


iso-8859-15
This is currently an alias for the Latin 1 set.


koi8-r The usual Russian set (RFC-1489).


utf-8 Bypass all translations and assume that the OS uses
native UTF-8 encoding.


--utf8-strings
--no-utf8-strings
Assume that command line arguments are given as UTF-8 strings.
The default (--no-utf8-strings) is to assume that arguments
are encoded in the character set as specified by
--display-charset. These options affect all following
arguments. Both options may be used multiple times. This
option should not be used in an option file.

This option has no effect on Windows. There the internal used
UTF-8 encoding is translated for console input and output.
The command line arguments are expected as Unicode and
translated to UTF-8. Thus when calling this program from
another, make sure to use the Unicode version of
CreateProcess.


--options file
Read options from file and do not try to read them from the
default options file in the homedir (see --homedir). This
option is ignored if used in an options file.


--no-options
Shortcut for --options /dev/null. This option is detected
before an attempt to open an option file. Using this option
will also prevent the creation of a `~/.gnupg' homedir.


-z n
--compress-level n
--bzip2-compress-level n
--no-compress
Set compression level to n for the ZIP and ZLIB compression
algorithms. The default is to use the default compression
level of zlib (normally 6). --bzip2-compress-level sets the
compression level for the BZIP2 compression algorithm
(defaulting to 6 as well). This is a different option from
--compress-level since BZIP2 uses a significant amount of
memory for each additional compression level.

Option -z sets both. A value of 0 for n disables compression.
A value of -1 forces compression using the default level.
Option --no-compress is identical to -z0.

Except for the --store command compression is always used
unless gpg detects that the input is already compressed. To
inhibit the use of compression use -z0 or --no-compress; to
force compression use -z-1 or option z with another
compression level than the default as indicated by -1. Note
that this overriding of the default deection works only with z
and not with the long variant of this option.


--bzip2-decompress-lowmem
Use a different decompression method for BZIP2 compressed
files. This alternate method uses a bit more than half the
memory, but also runs at half the speed. This is useful under
extreme low memory circumstances when the file was originally
compressed at a high --bzip2-compress-level.


--mangle-dos-filenames
--no-mangle-dos-filenames
Older version of Windows cannot handle filenames with more
than one dot. --mangle-dos-filenames causes GnuPG to replace
(rather than add to) the extension of an output filename to
avoid this problem. This option is off by default and has no
effect on non-Windows platforms.


--ask-cert-level
--no-ask-cert-level
When making a key signature, prompt for a certification level.
If this option is not specified, the certification level used
is set via --default-cert-level. See --default-cert-level for
information on the specific levels and how they are used.
--no-ask-cert-level disables this option. This option defaults
to no.


--default-cert-level n
The default to use for the check level when signing a key.

0 means you make no particular claim as to how carefully you
verified the key.

1 means you believe the key is owned by the person who claims
to own it but you could not, or did not verify the key at all.
This is useful for a "persona" verification, where you sign
the key of a pseudonymous user.

2 means you did casual verification of the key. For example,
this could mean that you verified the key fingerprint and
checked the user ID on the key against a photo ID.

3 means you did extensive verification of the key. For
example, this could mean that you verified the key fingerprint
with the owner of the key in person, and that you checked, by
means of a hard to forge document with a photo ID (such as a
passport) that the name of the key owner matches the name in
the user ID on the key, and finally that you verified (by
exchange of email) that the email address on the key belongs
to the key owner.

Note that the examples given above for levels 2 and 3 are just
that: examples. In the end, it is up to you to decide just
what "casual" and "extensive" mean to you.

This option defaults to 0 (no particular claim).


--min-cert-level
When building the trust database, treat any signatures with a
certification level below this as invalid. Defaults to 2,
which disregards level 1 signatures. Note that level 0 "no
particular claim" signatures are always accepted.


--trusted-key long key ID or fingerprint
Assume that the specified key (which should be given as
fingerprint) is as trustworthy as one of your own secret keys.
This option is useful if you don't want to keep your secret
keys (or one of them) online but still want to be able to
check the validity of a given recipient's or signator's key.
If the given key is not locally available but an LDAP
keyserver is configured the missing key is imported from that
server. The value "none" is explicitly allowed to distinguish
between the use of any trusted-key option and no use of this
option at all (e.g. due to the --no-options option).


--add-desig-revoker [sensitive:]fingerprint
Add the key specified by fingerprint as a designated revoker
to newly created keys. If the fingerprint is prefixed with
the keyword ``sensitive:'' that info is normally not exported
wit the key. This option may be given several time to add
more than one designated revoker. If the keyword ``clear'' is
used instead of a fingerprint, all designated options
previously encountered are discarded. Designated revokers are
marked on the key as non-revocable. Note that a designated
revoker specified using a parameter file will also be added to
the key.


--trust-model {pgp|classic|tofu|tofu+pgp|direct|always|auto}
Set what trust model GnuPG should follow. The models are:


pgp This is the Web of Trust combined with trust signatures
as used in PGP 5.x and later. This is the default trust
model when creating a new trust database.


classic
This is the standard Web of Trust as introduced by PGP
2.


tofu

TOFU stands for Trust On First Use. In this trust
model, the first time a key is seen, it is memorized.
If later another key with a user id with the same email
address is seen, both keys are marked as suspect. In
that case, the next time either is used, a warning is
displayed describing the conflict, why it might have
occurred (either the user generated a new key and
failed to cross sign the old and new keys, the key is
forgery, or a man-in-the-middle attack is being
attempted), and the user is prompted to manually
confirm the validity of the key in question.

Because a potential attacker is able to control the
email address and thereby circumvent the conflict
detection algorithm by using an email address that is
similar in appearance to a trusted email address,
whenever a message is verified, statistics about the
number of messages signed with the key are shown. In
this way, a user can easily identify attacks using fake
keys for regular correspondents.

When compared with the Web of Trust, TOFU offers
significantly weaker security guarantees. In
particular, TOFU only helps ensure consistency (that
is, that the binding between a key and email address
doesn't change). A major advantage of TOFU is that it
requires little maintenance to use correctly. To use
the web of trust properly, you need to actively sign
keys and mark users as trusted introducers. This is a
time-consuming process and anecdotal evidence suggests
that even security-conscious users rarely take the time
to do this thoroughly and instead rely on an ad-hoc
TOFU process.

In the TOFU model, policies are associated with
bindings between keys and email addresses (which are
extracted from user ids and normalized). There are
five policies, which can be set manually using the
--tofu-policy option. The default policy can be set
using the --tofu-default-policy option.

The TOFU policies are: auto, good, unknown, bad and
ask. The auto policy is used by default (unless
overridden by --tofu-default-policy) and marks a
binding as marginally trusted. The good, unknown and
bad policies mark a binding as fully trusted, as having
unknown trust or as having trust never, respectively.
The unknown policy is useful for just using TOFU to
detect conflicts, but to never assign positive trust to
a binding. The final policy, ask prompts the user to
indicate the binding's trust. If batch mode is enabled
(or input is inappropriate in the context), then the
user is not prompted and the undefined trust level is
returned.


tofu+pgp
This trust model combines TOFU with the Web of Trust.
This is done by computing the trust level for each
model and then taking the maximum trust level where the
trust levels are ordered as follows: unknown <
undefined < marginal < fully < ultimate < expired <
never.

By setting --tofu-default-policy=unknown, this model
can be used to implement the web of trust with TOFU's
conflict detection algorithm, but without its
assignment of positive trust values, which some
security-conscious users don't like.


direct Key validity is set directly by the user and not
calculated via the Web of Trust. This model is solely
based on the key and does not distinguish user IDs.
Note that when changing to another trust model the
trust values assigned to a key are transformed into
ownertrust values, which also indicate how you trust
the owner of the key to sign other keys.


always Skip key validation and assume that used keys are
always fully valid. You generally won't use this unless
you are using some external validation scheme. This
option also suppresses the "[uncertain]" tag printed
with signature checks when there is no evidence that
the user ID is bound to the key. Note that this trust
model still does not allow the use of expired, revoked,
or disabled keys.


auto Select the trust model depending on whatever the
internal trust database says. This is the default model
if such a database already exists. Note that a tofu
trust model is not considered here and must be enabled
explicitly.


--auto-key-locate mechanisms
--no-auto-key-locate
GnuPG can automatically locate and retrieve keys as needed
using this option. This happens when encrypting to an email
address (in the "user@example.com" form), and there are no
"user@example.com" keys on the local keyring. This option
takes any number of the mechanisms listed below, in the order
they are to be tried. Instead of listing the mechanisms as
comma delimited arguments, the option may also be given
several times to add more mechanism. The option
--no-auto-key-locate or the mechanism "clear" resets the list.
The default is "local,wkd".


cert Locate a key using DNS CERT, as specified in RFC-4398.


pka Locate a key using DNS PKA.


dane Locate a key using DANE, as specified in draft-ietf-
dane-openpgpkey-05.txt.


wkd Locate a key using the Web Key Directory protocol.


ldap Using DNS Service Discovery, check the domain in
question for any LDAP keyservers to use. If this
fails, attempt to locate the key using the PGP
Universal method of checking `ldap://keys.(thedomain)'.


ntds Locate the key using the Active Directory (Windows
only). This method also allows to search by
fingerprint using the command --locate-external-key.
Note that this mechanism is actually a shortcut for the
mechanism `keyserver' but using "ldap:///" as the
keyserver.


keyserver
Locate a key using a keyserver. This method also
allows to search by fingerprint using the command
--locate-external-key if any of the configured
keyservers is an LDAP server.


keyserver-URL
In addition, a keyserver URL as used in the dirmngr
configuration may be used here to query that particular
keyserver. This method also allows to search by
fingerprint using the command --locate-external-key if
the URL specifies an LDAP server.


local Locate the key using the local keyrings. This
mechanism allows the user to select the order a local
key lookup is done. Thus using `--auto-key-locate
local' is identical to --no-auto-key-locate.


nodefault
This flag disables the standard local key lookup, done
before any of the mechanisms defined by the
--auto-key-locate are tried. The position of this
mechanism in the list does not matter. It is not
required if local is also used.


clear Clear all defined mechanisms. This is useful to
override mechanisms given in a config file. Note that
a nodefault in mechanisms will also be cleared unless
it is given after the clear.


--auto-key-import
--no-auto-key-import
This is an offline mechanism to get a missing key for
signature verification and for later encryption to this key.
If this option is enabled and a signature includes an embedded
key, that key is used to verify the signature and on
verification success that key is imported. The default is
--no-auto-key-import.

On the sender (signing) site the option --include-key-block
needs to be used to put the public part of the signing key as
"Key Block subpacket" into the signature.


--auto-key-retrieve
--no-auto-key-retrieve
These options enable or disable the automatic retrieving of
keys from a keyserver when verifying signatures made by keys
that are not on the local keyring. The default is
--no-auto-key-retrieve.

The order of methods tried to lookup the key is:

1. If the option --auto-key-import is set and the signatures
includes an embedded key, that key is used to verify the
signature and on verification success that key is imported.

2. If a preferred keyserver is specified in the signature and
the option honor-keyserver-url is active (which is not the
default), that keyserver is tried. Note that the creator of
the signature uses the option --sig-keyserver-url to specify
the preferred keyserver for data signatures.

3. If the signature has the Signer's UID set (e.g. using
--sender while creating the signature) a Web Key Directory
(WKD) lookup is done. This is the default configuration but
can be disabled by removing WKD from the auto-key-locate list
or by using the option --disable-signer-uid.

4. If the option honor-pka-record is active, the legacy PKA
method is used.

5. If any keyserver is configured and the Issuer Fingerprint
is part of the signature (since GnuPG 2.1.16), the configured
keyservers are tried.

Note that this option makes a "web bug" like behavior
possible. Keyserver or Web Key Directory operators can see
which keys you request, so by sending you a message signed by
a brand new key (which you naturally will not have on your
local keyring), the operator can tell both your IP address and
the time when you verified the signature.


--keyid-format {none|short|0xshort|long|0xlong}
Select how to display key IDs. "none" does not show the key
ID at all but shows the fingerprint in a separate line.
"short" is the traditional 8-character key ID. "long" is the
more accurate (but less convenient) 16-character key ID. Add
an "0x" to either to include an "0x" at the beginning of the
key ID, as in 0x99242560. Note that this option is ignored if
the option --with-colons is used.


--keyserver name
This option is deprecated - please use the --keyserver in
`dirmngr.conf' instead.

Use name as your keyserver. This is the server that
--receive-keys, --send-keys, and --search-keys will
communicate with to receive keys from, send keys to, and
search for keys on. The format of the name is a URI:
`scheme:[//]keyservername[:port]' The scheme is the type of
keyserver: "hkp"/"hkps" for the HTTP (or compatible)
keyservers or "ldap"/"ldaps" for the LDAP keyservers. Note
that your particular installation of GnuPG may have other
keyserver types available as well. Keyserver schemes are case-
insensitive.

Most keyservers synchronize with each other, so there is
generally no need to send keys to more than one server. The
keyserver hkp://keys.gnupg.net uses round robin DNS to give a
different keyserver each time you use it.


--keyserver-options {name=value}
This is a space or comma delimited string that gives options
for the keyserver. Options can be prefixed with a `no-' to
give the opposite meaning. Valid import-options or export-
options may be used here as well to apply to importing
(--recv-key) or exporting (--send-key) a key from a keyserver.
While not all options are available for all keyserver types,
some common options are:


include-revoked
When searching for a key with --search-keys, include
keys that are marked on the keyserver as revoked. Note
that not all keyservers differentiate between revoked
and unrevoked keys, and for such keyservers this option
is meaningless. Note also that most keyservers do not
have cryptographic verification of key revocations, and
so turning this option off may result in skipping keys
that are incorrectly marked as revoked.


include-disabled
When searching for a key with --search-keys, include
keys that are marked on the keyserver as disabled. Note
that this option is not used with HKP keyservers.


auto-key-retrieve
This is an obsolete alias for the option
auto-key-retrieve. Please do not use it; it will be
removed in future versions..


honor-keyserver-url
When using --refresh-keys, if the key in question has a
preferred keyserver URL, then use that preferred
keyserver to refresh the key from. In addition, if
auto-key-retrieve is set, and the signature being
verified has a preferred keyserver URL, then use that
preferred keyserver to fetch the key from. Note that
this option introduces a "web bug": The creator of the
key can see when the keys is refreshed. Thus this
option is not enabled by default.


honor-pka-record
If --auto-key-retrieve is used, and the signature being
verified has a PKA record, then use the PKA information
to fetch the key. Defaults to "yes".


include-subkeys
When receiving a key, include subkeys as potential
targets. Note that this option is not used with HKP
keyservers, as they do not support retrieving keys by
subkey id.


timeout
http-proxy=value
verbose
debug
check-cert

ca-cert-file
These options have no more function since GnuPG 2.1.
Use the dirmngr configuration options instead.


The default list of options is: "self-sigs-only, import-clean,
repair-keys, repair-pks-subkey-bug, export-attributes, honor-pka-
record". However, if the actual used source is an LDAP server "no-
self-sigs-only" is assumed unless "self-sigs-only" has been explictly
configured.


--completes-needed n
Number of completely trusted users to introduce a new key
signer (defaults to 1).


--marginals-needed n
Number of marginally trusted users to introduce a new key
signer (defaults to 3)


--tofu-default-policy {auto|good|unknown|bad|ask}
The default TOFU policy (defaults to auto). For more
information about the meaning of this option, see: [trust-
model-tofu].


--max-cert-depth n
Maximum depth of a certification chain (default is 5).


--no-sig-cache
Do not cache the verification status of key signatures.
Caching gives a much better performance in key listings.
However, if you suspect that your public keyring is not safe
against write modifications, you can use this option to
disable the caching. It probably does not make sense to
disable it because all kind of damage can be done if someone
else has write access to your public keyring.


--auto-check-trustdb
--no-auto-check-trustdb
If GnuPG feels that its information about the Web of Trust has
to be updated, it automatically runs the --check-trustdb
command internally. This may be a time consuming process.
--no-auto-check-trustdb disables this option.


--use-agent
--no-use-agent
This is dummy option. gpg2 always requires the agent.


--gpg-agent-info
This is dummy option. It has no effect when used with gpg2.


--agent-program file
Specify an agent program to be used for secret key operations.
The default value is determined by running gpgconf with the
option --list-dirs. Note that the pipe symbol (|) is used for
a regression test suite hack and may thus not be used in the
file name.


--dirmngr-program file
Specify a dirmngr program to be used for keyserver access.
The default value is `/usr/bin/dirmngr'.


--disable-dirmngr
Entirely disable the use of the Dirmngr.


--no-autostart
Do not start the gpg-agent or the dirmngr if it has not yet
been started and its service is required. This option is
mostly useful on machines where the connection to gpg-agent
has been redirected to another machines. If dirmngr is
required on the remote machine, it may be started manually
using gpgconf --launch dirmngr.


--lock-once
Lock the databases the first time a lock is requested and do
not release the lock until the process terminates.


--lock-multiple
Release the locks every time a lock is no longer needed. Use
this to override a previous --lock-once from a config file.


--lock-never
Disable locking entirely. This option should be used only in
very special environments, where it can be assured that only
one process is accessing those files. A bootable floppy with a
stand-alone encryption system will probably use this. Improper
usage of this option may lead to data and key corruption.


--exit-on-status-write-error
This option will cause write errors on the status FD to
immediately terminate the process. That should in fact be the
default but it never worked this way and thus we need an
option to enable this, so that the change won't break
applications which close their end of a status fd connected
pipe too early. Using this option along with
--enable-progress-filter may be used to cleanly cancel long
running gpg operations.


--limit-card-insert-tries n
With n greater than 0 the number of prompts asking to insert a
smartcard gets limited to N-1. Thus with a value of 1 gpg
won't at all ask to insert a card if none has been inserted at
startup. This option is useful in the configuration file in
case an application does not know about the smartcard support
and waits ad infinitum for an inserted card.


--no-random-seed-file
GnuPG uses a file to store its internal random pool over
invocations. This makes random generation faster; however
sometimes write operations are not desired. This option can be
used to achieve that with the cost of slower random
generation.


--no-greeting
Suppress the initial copyright message.


--no-secmem-warning
Suppress the warning about "using insecure memory".


--no-permission-warning
Suppress the warning about unsafe file and home directory
(--homedir) permissions. Note that the permission checks that
GnuPG performs are not intended to be authoritative, but
rather they simply warn about certain common permission
problems. Do not assume that the lack of a warning means that
your system is secure.

Note that the warning for unsafe --homedir permissions cannot
be suppressed in the gpg.conf file, as this would allow an
attacker to place an unsafe gpg.conf file in place, and use
this file to suppress warnings about itself. The --homedir
permissions warning may only be suppressed on the command
line.


--require-secmem
--no-require-secmem
Refuse to run if GnuPG cannot get secure memory. Defaults to
no (i.e. run, but give a warning).


--require-cross-certification
--no-require-cross-certification
When verifying a signature made from a subkey, ensure that the
cross certification "back signature" on the subkey is present
and valid. This protects against a subtle attack against
subkeys that can sign. Defaults to
--require-cross-certification for gpg2.


--expert
--no-expert
Allow the user to do certain nonsensical or "silly" things
like signing an expired or revoked key, or certain potentially
incompatible things like generating unusual key types. This
also disables certain warning messages about potentially
incompatible actions. As the name implies, this option is for
experts only. If you don't fully understand the implications
of what it allows you to do, leave this off. --no-expert
disables this option.

Key related options

--recipient name
-r Encrypt for user id name. If this option or --hidden-recipient
is not specified, GnuPG asks for the user-id unless
--default-recipient is given.


--hidden-recipient name
-R Encrypt for user ID name, but hide the key ID of this user's
key. This option helps to hide the receiver of the message and
is a limited countermeasure against traffic analysis. If this
option or --recipient is not specified, GnuPG asks for the
user ID unless --default-recipient is given.


--recipient-file file
-f This option is similar to --recipient except that it encrypts
to a key stored in the given file. file must be the name of a
file containing exactly one key. gpg2 assumes that the key in
this file is fully valid.


--hidden-recipient-file file
-F This option is similar to --hidden-recipient except that it
encrypts to a key stored in the given file. file must be the
name of a file containing exactly one key. gpg2 assumes that
the key in this file is fully valid.


--encrypt-to name
Same as --recipient but this one is intended for use in the
options file and may be used with your own user-id as an
"encrypt-to-self". These keys are only used when there are
other recipients given either by use of --recipient or by the
asked user id. No trust checking is performed for these user
ids and even disabled keys can be used.


--hidden-encrypt-to name
Same as --hidden-recipient but this one is intended for use in
the options file and may be used with your own user-id as a
hidden "encrypt-to-self". These keys are only used when there
are other recipients given either by use of --recipient or by
the asked user id. No trust checking is performed for these
user ids and even disabled keys can be used.


--no-encrypt-to
Disable the use of all --encrypt-to and --hidden-encrypt-to
keys.


--group {name=value}
Sets up a named group, which is similar to aliases in email
programs. Any time the group name is a recipient (-r or
--recipient), it will be expanded to the values specified.
Multiple groups with the same name are automatically merged
into a single group.

The values are key IDs or fingerprints, but any key
description is accepted. Note that a value with spaces in it
will be treated as two different values. Note also there is
only one level of expansion --- you cannot make an group that
points to another group. When used from the command line, it
may be necessary to quote the argument to this option to
prevent the shell from treating it as multiple arguments.


--ungroup name
Remove a given entry from the --group list.


--no-groups
Remove all entries from the --group list.


--local-user name
-u Use name as the key to sign with. Note that this option
overrides --default-key.


--sender mbox
This option has two purposes. mbox must either be a complete
user id with a proper mail address or just a mail address.
When creating a signature this option tells gpg the user id of
a key used to make a signature if the key was not directly
specified by a user id. When verifying a signature the mbox
is used to restrict the information printed by the TOFU code
to matching user ids.


--try-secret-key name
For hidden recipients GPG needs to know the keys to use for
trial decryption. The key set with --default-key is always
tried first, but this is often not sufficient. This option
allows setting more keys to be used for trial decryption.
Although any valid user-id specification may be used for name
it makes sense to use at least the long keyid to avoid
ambiguities. Note that gpg-agent might pop up a pinentry for
a lot keys to do the trial decryption. If you want to stop
all further trial decryption you may use close-window button
instead of the cancel button.


--try-all-secrets
Don't look at the key ID as stored in the message but try all
secret keys in turn to find the right decryption key. This
option forces the behaviour as used by anonymous recipients
(created by using --throw-keyids or --hidden-recipient) and
might come handy in case where an encrypted message contains a
bogus key ID.


--skip-hidden-recipients
--no-skip-hidden-recipients
During decryption skip all anonymous recipients. This option
helps in the case that people use the hidden recipients
feature to hide their own encrypt-to key from others. If one
has many secret keys this may lead to a major annoyance
because all keys are tried in turn to decrypt something which
was not really intended for it. The drawback of this option
is that it is currently not possible to decrypt a message
which includes real anonymous recipients.

Input and Output

--armor
-a Create ASCII armored output. The default is to create the
binary OpenPGP format.


--no-armor
Assume the input data is not in ASCII armored format.


--output file
-o file
Write output to file. To write to stdout use - as the
filename.


--max-output n
This option sets a limit on the number of bytes that will be
generated when processing a file. Since OpenPGP supports
various levels of compression, it is possible that the
plaintext of a given message may be significantly larger than
the original OpenPGP message. While GnuPG works properly with
such messages, there is often a desire to set a maximum file
size that will be generated before processing is forced to
stop by the OS limits. Defaults to 0, which means "no limit".


--input-size-hint n
This option can be used to tell GPG the size of the input data
in bytes. n must be a positive base-10 number. This option
is only useful if the input is not taken from a file. GPG may
use this hint to optimize its buffer allocation strategy. It
is also used by the --status-fd line ``PROGRESS'' to provide a
value for ``total'' if that is not available by other means.


--key-origin string[,url]
gpg can track the origin of a key. Certain origins are
implicitly known (e.g. keyserver, web key directory) and set.
For a standard import the origin of the keys imported can be
set with this option. To list the possible values use "help"
for string. Some origins can store an optional url argument.
That URL can appended to string after a comma.


--import-options parameters
This is a space or comma delimited string that gives options
for importing keys. Options can be prepended with a `no-' to
give the opposite meaning. The options are:


import-local-sigs
Allow importing key signatures marked as "local". This
is not generally useful unless a shared keyring scheme
is being used. Defaults to no.


keep-ownertrust
Normally possible still existing ownertrust values of a
key are cleared if a key is imported. This is in
general desirable so that a formerly deleted key does
not automatically gain an ownertrust values merely due
to import. On the other hand it is sometimes necessary
to re-import a trusted set of keys again but keeping
already assigned ownertrust values. This can be
achieved by using this option.


repair-pks-subkey-bug
During import, attempt to repair the damage caused by
the PKS keyserver bug (pre version 0.9.6) that mangles
keys with multiple subkeys. Note that this cannot
completely repair the damaged key as some crucial data
is removed by the keyserver, but it does at least give
you back one subkey. Defaults to no for regular
--import and to yes for keyserver --receive-keys.


import-show
show-only
Show a listing of the key as imported right before it
is stored. This can be combined with the option
--dry-run to only look at keys; the option show-only is
a shortcut for this combination. The command
--show-keys is another shortcut for this. Note that
suffixes like '#' for "sec" and "sbb" lines may or may
not be printed.


import-export
Run the entire import code but instead of storing the
key to the local keyring write it to the output. The
export options export-pka and export-dane affect the
output. This option can be used to remove all invalid
parts from a key without the need to store it.


merge-only
During import, allow key updates to existing keys, but
do not allow any new keys to be imported. Defaults to
no.


import-clean
After import, compact (remove all signatures except the
self-signature) any user IDs from the new key that are
not usable. Then, remove any signatures from the new
key that are not usable. This includes signatures that
were issued by keys that are not present on the
keyring. This option is the same as running the
--edit-key command "clean" after import. Defaults to
no.


self-sigs-only
Accept only self-signatures while importing a key. All
other key signatures are skipped at an early import
stage. This option can be used with keyserver-options
to mitigate attempts to flood a key with bogus
signatures from a keyserver. The drawback is that all
other valid key signatures, as required by the Web of
Trust are also not imported. Note that when using this
option along with import-clean it suppresses the final
clean step after merging the imported key into the
existing key.


repair-keys
After import, fix various problems with the keys. For
example, this reorders signatures, and strips duplicate
signatures. Defaults to yes.


import-minimal
Import the smallest key possible. This removes all
signatures except the most recent self-signature on
each user ID. This option is the same as running the
--edit-key command "minimize" after import. Defaults
to no.


restore
import-restore
Import in key restore mode. This imports all data
which is usually skipped during import; including all
GnuPG specific data. All other contradicting options
are overridden.


--import-filter {name=expr}
--export-filter {name=expr}
These options define an import/export filter which are applied
to the imported/exported keyblock right before it will be
stored/written. name defines the type of filter to use, expr
the expression to evaluate. The option can be used several
times which then appends more expression to the same name.


The available filter types are:


keep-uid
This filter will keep a user id packet and its
dependent packets in the keyblock if the expression
evaluates to true.


drop-subkey
This filter drops the selected subkeys. Currently only
implemented for --export-filter.


drop-sig
This filter drops the selected key signatures on user
ids. Self-signatures are not considered. Currently
only implemented for --import-filter.


For the syntax of the expression see the chapter "FILTER
EXPRESSIONS". The property names for the expressions depend on the
actual filter type and are indicated in the following table.

The available properties are:


uid A string with the user id. (keep-uid)


mbox The addr-spec part of a user id with mailbox or the
empty string. (keep-uid)


key_algo
A number with the public key algorithm of a key or
subkey packet. (drop-subkey)


key_created
key_created_d
The first is the timestamp a public key or subkey
packet was created. The second is the same but given
as an ISO string, e.g. "2016-08-17". (drop-subkey)


fpr The hexified fingerprint of the current subkey or
primary key. (drop-subkey)


primary
Boolean indicating whether the user id is the primary
one. (keep-uid)


expired
Boolean indicating whether a user id (keep-uid), a key
(drop-subkey), or a signature (drop-sig) expired.


revoked
Boolean indicating whether a user id (keep-uid) or a
key (drop-subkey) has been revoked.


disabled
Boolean indicating whether a primary key is disabled.
(not used)


secret Boolean indicating whether a key or subkey is a secret
one. (drop-subkey)


usage A string indicating the usage flags for the subkey,
from the sequence ``ecsa?''. For example, a subkey
capable of just signing and authentication would be an
exact match for ``sa''. (drop-subkey)


sig_created
sig_created_d
The first is the timestamp a signature packet was
created. The second is the same but given as an ISO
date string, e.g. "2016-08-17". (drop-sig)


sig_algo
A number with the public key algorithm of a signature
packet. (drop-sig)


sig_digest_algo
A number with the digest algorithm of a signature
packet. (drop-sig)


--export-options parameters
This is a space or comma delimited string that gives options
for exporting keys. Options can be prepended with a `no-' to
give the opposite meaning. The options are:


export-local-sigs
Allow exporting key signatures marked as "local". This
is not generally useful unless a shared keyring scheme
is being used. Defaults to no.


export-attributes
Include attribute user IDs (photo IDs) while exporting.
Not including attribute user IDs is useful to export
keys that are going to be used by an OpenPGP program
that does not accept attribute user IDs. Defaults to
yes.


export-sensitive-revkeys
Include designated revoker information that was marked
as "sensitive". Defaults to no.


backup
export-backup
Export for use as a backup. The exported data includes
all data which is needed to restore the key or keys
later with GnuPG. The format is basically the OpenPGP
format but enhanced with GnuPG specific data. All
other contradicting options are overridden.


export-clean
Compact (remove all signatures from) user IDs on the
key being exported if the user IDs are not usable.
Also, do not export any signatures that are not usable.
This includes signatures that were issued by keys that
are not present on the keyring. This option is the same
as running the --edit-key command "clean" before export
except that the local copy of the key is not modified.
Defaults to no.


export-minimal
Export the smallest key possible. This removes all
signatures except the most recent self-signature on
each user ID. This option is the same as running the
--edit-key command "minimize" before export except that
the local copy of the key is not modified. Defaults to
no.


export-pka
Instead of outputting the key material output PKA
records suitable to put into DNS zone files. An ORIGIN
line is printed before each record to allow diverting
the records to the corresponding zone file.


export-revocs
Export only standalone revocation certificates of the
key. This option does not export revocations of 3rd
party certificate revocations.


export-dane
Instead of outputting the key material output OpenPGP
DANE records suitable to put into DNS zone files. An
ORIGIN line is printed before each record to allow
diverting the records to the corresponding zone file.


--with-colons
Print key listings delimited by colons. Note that the output
will be encoded in UTF-8 regardless of any --display-charset
setting. This format is useful when GnuPG is called from
scripts and other programs as it is easily machine parsed. The
details of this format are documented in the file
`doc/DETAILS', which is included in the GnuPG source
distribution.


--fixed-list-mode
Do not merge primary user ID and primary key in --with-colon
listing mode and print all timestamps as seconds since
1970-01-01. Since GnuPG 2.0.10, this mode is always used and
thus this option is obsolete; it does not harm to use it
though.


--legacy-list-mode
Revert to the pre-2.1 public key list mode. This only affects
the human readable output and not the machine interface (i.e.
--with-colons). Note that the legacy format does not convey
suitable information for elliptic curves.


--with-fingerprint
Same as the command --fingerprint but changes only the format
of the output and may be used together with another command.


--with-subkey-fingerprint
If a fingerprint is printed for the primary key, this option
forces printing of the fingerprint for all subkeys. This
could also be achieved by using the --with-fingerprint twice
but by using this option along with keyid-format "none" a
compact fingerprint is printed.


--with-icao-spelling
Print the ICAO spelling of the fingerprint in addition to the
hex digits.


--with-keygrip
Include the keygrip in the key listings. In --with-colons
mode this is implicitly enable for secret keys.


--with-key-origin
Include the locally held information on the origin and last
update of a key in a key listing. In --with-colons mode this
is always printed. This data is currently experimental and
shall not be considered part of the stable API.


--with-wkd-hash
Print a Web Key Directory identifier along with each user ID
in key listings. This is an experimental feature and
semantics may change.


--with-secret
Include info about the presence of a secret key in public key
listings done with --with-colons.

OpenPGP protocol specific options

-t, --textmode
--no-textmode
Treat input files as text and store them in the OpenPGP
canonical text form with standard "CRLF" line endings. This
also sets the necessary flags to inform the recipient that the
encrypted or signed data is text and may need its line endings
converted back to whatever the local system uses. This option
is useful when communicating between two platforms that have
different line ending conventions (UNIX-like to Mac, Mac to
Windows, etc). --no-textmode disables this option, and is the
default.


--force-v3-sigs
--no-force-v3-sigs

--force-v4-certs
--no-force-v4-certs
These options are obsolete and have no effect since GnuPG 2.1.


--force-ocb
Force the use of OCB mode encryption instead of CFB+MDC
encryption. OCB is a modern and faster way to do
authenticated encryption than the older CFB+MDC method. This
option is only useful for symmetric-only encryption because
the mode is automatically selected based on the preferences of
the recipients's public keys.


--force-mdc
--disable-mdc
These options are obsolete and have no effect since GnuPG
2.2.8. The MDC is always used. But note: If the creation of
a legacy non-MDC message is exceptionally required, the option
--rfc2440 allows for this.


--disable-signer-uid
By default the user ID of the signing key is embedded in the
data signature. As of now this is only done if the signing
key has been specified with local-user using a mail address,
or with sender. This information can be helpful for verifier
to locate the key; see option --auto-key-retrieve.


--include-key-block
This option is used to embed the actual signing key into a
data signature. The embedded key is stripped down to a single
user id and includes only the signing subkey used to create
the signature as well as as valid encryption subkeys. All
other info is removed from the key to keep it and thus the
signature small. This option is the OpenPGP counterpart to
the gpgsm option --include-certs.


--personal-cipher-preferences string
Set the list of personal cipher preferences to string. Use
gpg2 --version to get a list of available algorithms, and use
none to set no preference at all. This allows the user to
safely override the algorithm chosen by the recipient key
preferences, as GPG will only select an algorithm that is
usable by all recipients. The most highly ranked cipher in
this list is also used for the --symmetric encryption command.


--personal-digest-preferences string
Set the list of personal digest preferences to string. Use
gpg2 --version to get a list of available algorithms, and use
none to set no preference at all. This allows the user to
safely override the algorithm chosen by the recipient key
preferences, as GPG will only select an algorithm that is
usable by all recipients. The most highly ranked digest
algorithm in this list is also used when signing without
encryption (e.g. --clear-sign or --sign).


--personal-compress-preferences string
Set the list of personal compression preferences to string.
Use gpg2 --version to get a list of available algorithms, and
use none to set no preference at all. This allows the user to
safely override the algorithm chosen by the recipient key
preferences, as GPG will only select an algorithm that is
usable by all recipients. The most highly ranked compression
algorithm in this list is also used when there are no
recipient keys to consider (e.g. --symmetric).


--s2k-cipher-algo name
Use name as the cipher algorithm for symmetric encryption with
a passphrase if --personal-cipher-preferences and
--cipher-algo are not given. The default is AES-128.


--s2k-digest-algo name
Use name as the digest algorithm used to mangle the
passphrases for symmetric encryption. The default is SHA-1.


--s2k-mode n
Selects how passphrases for symmetric encryption are mangled.
If n is 0 a plain passphrase (which is in general not
recommended) will be used, a 1 adds a salt (which should not
be used) to the passphrase and a 3 (the default) iterates the
whole process a number of times (see --s2k-count).


--s2k-count n
Specify how many times the passphrases mangling for symmetric
encryption is repeated. This value may range between 1024 and
65011712 inclusive. The default is inquired from gpg-agent.
Note that not all values in the 1024-65011712 range are legal
and if an illegal value is selected, GnuPG will round up to
the nearest legal value. This option is only meaningful if
--s2k-mode is set to the default of 3.

Compliance options

These options control what GnuPG is compliant to. Only one of these
options may be active at a time. Note that the default setting of
this is nearly always the correct one. See the INTEROPERABILITY WITH
OTHER OPENPGP PROGRAMS section below before using one of these
options.


--gnupg
Use standard GnuPG behavior. This is essentially OpenPGP
behavior (see --openpgp), but with some additional workarounds
for common compatibility problems in different versions of
PGP. This is the default option, so it is not generally
needed, but it may be useful to override a different
compliance option in the gpg.conf file.


--openpgp
Reset all packet, cipher and digest options to strict OpenPGP
behavior. Use this option to reset all previous options like
--s2k-*, --cipher-algo, --digest-algo and --compress-algo to
OpenPGP compliant values. All PGP workarounds are disabled.


--rfc4880
Reset all packet, cipher and digest options to strict RFC-4880
behavior. Note that this is currently the same thing as
--openpgp.


--rfc4880bis
Enable experimental features from proposed updates to
RFC-4880. This option can be used in addition to the other
compliance options. Warning: The behavior may change with any
GnuPG release and created keys or data may not be usable with
future GnuPG versions.


--rfc2440
Reset all packet, cipher and digest options to strict RFC-2440
behavior. Note that by using this option encryption packets
are created in a legacy mode without MDC protection. This is
dangerous and should thus only be used for experiments. See
also option --ignore-mdc-error.


--pgp6 Set up all options to be as PGP 6 compliant as possible. This
restricts you to the ciphers IDEA (if the IDEA plugin is
installed), 3DES, and CAST5, the hashes MD5, SHA1 and
RIPEMD160, and the compression algorithms none and ZIP. This
also disables --throw-keyids, and making signatures with
signing subkeys as PGP 6 does not understand signatures made
by signing subkeys.

This option implies --escape-from-lines.


--pgp7 Set up all options to be as PGP 7 compliant as possible. This
is identical to --pgp6 except that MDCs are not disabled, and
the list of allowable ciphers is expanded to add AES128,
AES192, AES256, and TWOFISH.


--pgp8 Set up all options to be as PGP 8 compliant as possible. PGP 8
is a lot closer to the OpenPGP standard than previous versions
of PGP, so all this does is disable --throw-keyids and set
--escape-from-lines. All algorithms are allowed except for
the SHA224, SHA384, and SHA512 digests.


--compliance string
This option can be used instead of one of the options above.
Valid values for string are the above option names (without
the double dash) and possibly others as shown when using
"help" for string.


--min-rsa-length n
This option adjusts the compliance mode "de-vs" for stricter
key size requirements. For example, a value of 3000 turns
rsa2048 and dsa2048 keys into non-VS-NfD compliant keys.


--require-compliance
To check that data has been encrypted according to the rules
of the current compliance mode, a gpg user needs to evaluate
the status lines. This is allows frontends to handle
compliance check in a more flexible way. However, for
scripted use the required evaluation of the status-line
requires quite some effort; this option can be used instead to
make sure that the gpg process exits with a failure if the
compliance rules are not fulfilled. Note that this option has
currently an effect only in "de-vs" mode.


Doing things one usually doesn't want to do


-n
--dry-run
Don't make any changes (this is not completely implemented).


--list-only
Changes the behaviour of some commands. This is like --dry-run
but different in some cases. The semantic of this option may
be extended in the future. Currently it only skips the actual
decryption pass and therefore enables a fast listing of the
encryption keys.


-i
--interactive
Prompt before overwriting any files.


--compatibility-flags flags
Set compatibility flags to work around problems due to non-
compliant keys or data. The flags are given as a comma
separated list of flag names and are OR-ed together. The
special flag "none" clears the list and allows to start over
with an empty list. To get a list of available flags the sole
word "help" can be used.


--debug-level level
Select the debug level for investigating problems. level may
be a numeric value or by a keyword:


none No debugging at all. A value of less than 1 may be
used instead of the keyword.

basic Some basic debug messages. A value between 1 and 2 may
be used instead of the keyword.

advanced
More verbose debug messages. A value between 3 and 5
may be used instead of the keyword.

expert Even more detailed messages. A value between 6 and 8
may be used instead of the keyword.

guru All of the debug messages you can get. A value greater
than 8 may be used instead of the keyword. The
creation of hash tracing files is only enabled if the
keyword is used.

How these messages are mapped to the actual debugging flags is not
specified and may change with newer releases of this program. They
are however carefully selected to best aid in debugging.


--debug flags
Set debugging flags. All flags are or-ed and flags may be
given in C syntax (e.g. 0x0042) or as a comma separated list
of flag names. To get a list of all supported flags the
single word "help" can be used.


--debug-all
Set all useful debugging flags.


--debug-iolbf
Set stdout into line buffered mode. This option is only
honored when given on the command line.


--faked-system-time epoch
This option is only useful for testing; it sets the system
time back or forth to epoch which is the number of seconds
elapsed since the year 1970. Alternatively epoch may be given
as a full ISO time string (e.g. "20070924T154812").

If you suffix epoch with an exclamation mark (!), the system
time will appear to be frozen at the specified time.


--enable-progress-filter
Enable certain PROGRESS status outputs. This option allows
frontends to display a progress indicator while gpg is
processing larger files. There is a slight performance
overhead using it.


--status-fd n
Write special status strings to the file descriptor n. See
the file DETAILS in the documentation for a listing of them.


--status-file file
Same as --status-fd, except the status data is written to file
file.


--logger-fd n
Write log output to file descriptor n and not to STDERR.


--log-file file
--logger-file file
Same as --logger-fd, except the logger data is written to file
file. Use `socket://' to log to a socket. Note that in this
version of gpg the option has only an effect if --batch is
also used.


--attribute-fd n
Write attribute subpackets to the file descriptor n. This is
most useful for use with --status-fd, since the status
messages are needed to separate out the various subpackets
from the stream delivered to the file descriptor.


--attribute-file file
Same as --attribute-fd, except the attribute data is written
to file file.


--comment string
--no-comments
Use string as a comment string in cleartext signatures and
ASCII armored messages or keys (see --armor). The default
behavior is not to use a comment string. --comment may be
repeated multiple times to get multiple comment strings.
--no-comments removes all comments. It is a good idea to keep
the length of a single comment below 60 characters to avoid
problems with mail programs wrapping such lines. Note that
comment lines, like all other header lines, are not protected
by the signature.


--emit-version
--no-emit-version
Force inclusion of the version string in ASCII armored output.
If given once only the name of the program and the major
number is emitted, given twice the minor is also emitted,
given thrice the micro is added, and given four times an
operating system identification is also emitted.
--no-emit-version (default) disables the version line.


--sig-notation {name=value}
--cert-notation {name=value}
-N, --set-notation {name=value}
Put the name value pair into the signature as notation data.
name must consist only of printable characters or spaces, and
must contain a '@' character in the form
keyname@domain.example.com (substituting the appropriate
keyname and domain name, of course). This is to help prevent
pollution of the IETF reserved notation namespace. The
--expert flag overrides the '@' check. value may be any
printable string; it will be encoded in UTF-8, so you should
check that your --display-charset is set correctly. If you
prefix name with an exclamation mark (!), the notation data
will be flagged as critical (rfc4880:5.2.3.16). --sig-notation
sets a notation for data signatures. --cert-notation sets a
notation for key signatures (certifications). --set-notation
sets both.

There are special codes that may be used in notation names.
"%k" will be expanded into the key ID of the key being signed,
"%K" into the long key ID of the key being signed, "%f" into
the fingerprint of the key being signed, "%s" into the key ID
of the key making the signature, "%S" into the long key ID of
the key making the signature, "%g" into the fingerprint of the
key making the signature (which might be a subkey), "%p" into
the fingerprint of the primary key of the key making the
signature, "%c" into the signature count from the OpenPGP
smartcard, and "%%" results in a single "%". %k, %K, and %f
are only meaningful when making a key signature
(certification), and %c is only meaningful when using the
OpenPGP smartcard.


--known-notation name
Adds name to a list of known critical signature notations.
The effect of this is that gpg will not mark a signature with
a critical signature notation of that name as bad. Note that
gpg already knows by default about a few critical signatures
notation names.


--sig-policy-url string
--cert-policy-url string
--set-policy-url string
Use string as a Policy URL for signatures (rfc4880:5.2.3.20).
If you prefix it with an exclamation mark (!), the policy URL
packet will be flagged as critical. --sig-policy-url sets a
policy url for data signatures. --cert-policy-url sets a
policy url for key signatures (certifications).
--set-policy-url sets both.

The same %-expandos used for notation data are available here
as well.


--sig-keyserver-url string
Use string as a preferred keyserver URL for data signatures.
If you prefix it with an exclamation mark (!), the keyserver
URL packet will be flagged as critical.

The same %-expandos used for notation data are available here
as well.


--set-filename string
Use string as the filename which is stored inside messages.
This overrides the default, which is to use the actual
filename of the file being encrypted. Using the empty string
for string effectively removes the filename from the output.


--for-your-eyes-only
--no-for-your-eyes-only
Set the `for your eyes only' flag in the message. This causes
GnuPG to refuse to save the file unless the --output option is
given, and PGP to use a "secure viewer" with a claimed
Tempest-resistant font to display the message. This option
overrides --set-filename. --no-for-your-eyes-only disables
this option.


--use-embedded-filename
--no-use-embedded-filename
Try to create a file with a name as embedded in the data. This
can be a dangerous option as it enables overwriting files.
Defaults to no. Note that the option --output overrides this
option.


--cipher-algo name
Use name as cipher algorithm. Running the program with the
command --version yields a list of supported algorithms. If
this is not used the cipher algorithm is selected from the
preferences stored with the key. In general, you do not want
to use this option as it allows you to violate the OpenPGP
standard. --personal-cipher-preferences is the safe way to
accomplish the same thing.


--digest-algo name
Use name as the message digest algorithm. Running the program
with the command --version yields a list of supported
algorithms. In general, you do not want to use this option as
it allows you to violate the OpenPGP standard.
--personal-digest-preferences is the safe way to accomplish
the same thing.


--compress-algo name
Use compression algorithm name. "zlib" is RFC-1950 ZLIB
compression. "zip" is RFC-1951 ZIP compression which is used
by PGP. "bzip2" is a more modern compression scheme that can
compress some things better than zip or zlib, but at the cost
of more memory used during compression and decompression.
"uncompressed" or "none" disables compression. If this option
is not used, the default behavior is to examine the recipient
key preferences to see which algorithms the recipient
supports. If all else fails, ZIP is used for maximum
compatibility.

ZLIB may give better compression results than ZIP, as the
compression window size is not limited to 8k. BZIP2 may give
even better compression results than that, but will use a
significantly larger amount of memory while compressing and
decompressing. This may be significant in low memory
situations. Note, however, that PGP (all versions) only
supports ZIP compression. Using any algorithm other than ZIP
or "none" will make the message unreadable with PGP. In
general, you do not want to use this option as it allows you
to violate the OpenPGP standard.
--personal-compress-preferences is the safe way to accomplish
the same thing.


--cert-digest-algo name
Use name as the message digest algorithm used when signing a
key. Running the program with the command --version yields a
list of supported algorithms. Be aware that if you choose an
algorithm that GnuPG supports but other OpenPGP
implementations do not, then some users will not be able to
use the key signatures you make, or quite possibly your entire
key.


--disable-cipher-algo name
Never allow the use of name as cipher algorithm. The given
name will not be checked so that a later loaded algorithm will
still get disabled.


--disable-pubkey-algo name
Never allow the use of name as public key algorithm. The
given name will not be checked so that a later loaded
algorithm will still get disabled.


--throw-keyids
--no-throw-keyids
Do not put the recipient key IDs into encrypted messages. This
helps to hide the receivers of the message and is a limited
countermeasure against traffic analysis. ([Using a little
social engineering anyone who is able to decrypt the message
can check whether one of the other recipients is the one he
suspects.]) On the receiving side, it may slow down the
decryption process because all available secret keys must be
tried. --no-throw-keyids disables this option. This option is
essentially the same as using --hidden-recipient for all
recipients.


--not-dash-escaped
This option changes the behavior of cleartext signatures so
that they can be used for patch files. You should not send
such an armored file via email because all spaces and line
endings are hashed too. You can not use this option for data
which has 5 dashes at the beginning of a line, patch files
don't have this. A special armor header line tells GnuPG about
this cleartext signature option.


--escape-from-lines
--no-escape-from-lines
Because some mailers change lines starting with "From " to
">From " it is good to handle such lines in a special way when
creating cleartext signatures to prevent the mail system from
breaking the signature. Note that all other PGP versions do it
this way too. Enabled by default. --no-escape-from-lines
disables this option.


--passphrase-repeat n
Specify how many times gpg2 will request a new passphrase be
repeated. This is useful for helping memorize a passphrase.
Defaults to 1 repetition; can be set to 0 to disable any
passphrase repetition. Note that a n greater than 1 will pop
up the pinentry window n+1 times even if a modern pinentry
with two entry fields is used.


--passphrase-fd n
Read the passphrase from file descriptor n. Only the first
line will be read from file descriptor n. If you use 0 for n,
the passphrase will be read from STDIN. This can only be used
if only one passphrase is supplied.

Note that since Version 2.0 this passphrase is only used if
the option --batch has also been given. Since Version 2.1 the
--pinentry-mode also needs to be set to loopback.


--passphrase-file file
Read the passphrase from file file. Only the first line will
be read from file file. This can only be used if only one
passphrase is supplied. Obviously, a passphrase stored in a
file is of questionable security if other users can read this
file. Don't use this option if you can avoid it.

Note that since Version 2.0 this passphrase is only used if
the option --batch has also been given. Since Version 2.1 the
--pinentry-mode also needs to be set to loopback.


--passphrase string
Use string as the passphrase. This can only be used if only
one passphrase is supplied. Obviously, this is of very
questionable security on a multi-user system. Don't use this
option if you can avoid it.

Note that since Version 2.0 this passphrase is only used if
the option --batch has also been given. Since Version 2.1 the
--pinentry-mode also needs to be set to loopback.


--pinentry-mode mode
Set the pinentry mode to mode. Allowed values for mode are:

default
Use the default of the agent, which is ask.

ask Force the use of the Pinentry.

cancel Emulate use of Pinentry's cancel button.

error Return a Pinentry error (``No Pinentry'').

loopback
Redirect Pinentry queries to the caller. Note that in
contrast to Pinentry the user is not prompted again if
he enters a bad password.


--no-symkey-cache
Disable the passphrase cache used for symmetrical en- and
decryption. This cache is based on the message specific salt
value (cf. --s2k-mode).


--request-origin origin
Tell gpg to assume that the operation ultimately originated at
origin. Depending on the origin certain restrictions are
applied and the Pinentry may include an extra note on the
origin. Supported values for origin are: local which is the
default, remote to indicate a remote origin or browser for an
operation requested by a web browser.


--command-fd n
This is a replacement for the deprecated shared-memory IPC
mode. If this option is enabled, user input on questions is
not expected from the TTY but from the given file descriptor.
It should be used together with --status-fd. See the file
doc/DETAILS in the source distribution for details on how to
use it.


--command-file file
Same as --command-fd, except the commands are read out of file
file


--allow-non-selfsigned-uid
--no-allow-non-selfsigned-uid
Allow the import and use of keys with user IDs which are not
self-signed. This is not recommended, as a non self-signed
user ID is trivial to forge. --no-allow-non-selfsigned-uid
disables.


--allow-freeform-uid
Disable all checks on the form of the user ID while generating
a new one. This option should only be used in very special
environments as it does not ensure the de-facto standard
format of user IDs.


--ignore-time-conflict
GnuPG normally checks that the timestamps associated with keys
and signatures have plausible values. However, sometimes a
signature seems to be older than the key due to clock
problems. This option makes these checks just a warning. See
also --ignore-valid-from for timestamp issues on subkeys.


--ignore-valid-from
GnuPG normally does not select and use subkeys created in the
future. This option allows the use of such keys and thus
exhibits the pre-1.0.7 behaviour. You should not use this
option unless there is some clock problem. See also
--ignore-time-conflict for timestamp issues with signatures.


--ignore-crc-error
The ASCII armor used by OpenPGP is protected by a CRC checksum
against transmission errors. Occasionally the CRC gets mangled
somewhere on the transmission channel but the actual content
(which is protected by the OpenPGP protocol anyway) is still
okay. This option allows GnuPG to ignore CRC errors.


--ignore-mdc-error
This option changes a MDC integrity protection failure into a
warning. It is required to decrypt old messages which did not
use an MDC. It may also be useful if a message is partially
garbled, but it is necessary to get as much data as possible
out of that garbled message. Be aware that a missing or
failed MDC can be an indication of an attack. Use with great
caution; see also option --rfc2440.


--allow-weak-digest-algos
Signatures made with known-weak digest algorithms are normally
rejected with an ``invalid digest algorithm'' message. This
option allows the verification of signatures made with such
weak algorithms. MD5 is the only digest algorithm considered
weak by default. See also --weak-digest to reject other
digest algorithms.


--weak-digest name
Treat the specified digest algorithm as weak. Signatures made
over weak digests algorithms are normally rejected. This
option can be supplied multiple times if multiple algorithms
should be considered weak. See also --allow-weak-digest-algos
to disable rejection of weak digests. MD5 is always
considered weak, and does not need to be listed explicitly.


--allow-weak-key-signatures
To avoid a minor risk of collision attacks on third-party key
signatures made using SHA-1, those key signatures are
considered invalid. This options allows to override this
restriction.


--override-compliance-check
This was a temporary introduced option and has no more effect.


--no-default-keyring
Do not add the default keyring to the list of keyrings. Note
that GnuPG needs for almost all operations a keyring. Thus if
you use this option and do not provide alternate keyrings via
--keyring, then GnuPG will still use the default keyring.


--no-keyring
Do not use any keyring at all. This overrides the default and
all options which specify keyrings.


--skip-verify
Skip the signature verification step. This may be used to make
the decryption faster if the signature verification is not
needed.


--with-key-data
Print key listings delimited by colons (like --with-colons)
and print the public key data.


--list-signatures
--list-sigs
Same as --list-keys, but the signatures are listed too. This
command has the same effect as using --list-keys with
--with-sig-list. Note that in contrast to --check-signatures
the key signatures are not verified. This command can be used
to create a list of signing keys missing in the local keyring;
for example:

gpg --list-sigs --with-colons USERID | \
awk -F: '$1=="sig" && $2=="?" {if($13){print $13}else{print $5}}'


--fast-list-mode
Changes the output of the list commands to work faster; this
is achieved by leaving some parts empty. Some applications
don't need the user ID and the trust information given in the
listings. By using this options they can get a faster listing.
The exact behaviour of this option may change in future
versions. If you are missing some information, don't use this
option.


--no-literal
This is not for normal use. Use the source to see for what it
might be useful.


--set-filesize
This is not for normal use. Use the source to see for what it
might be useful.


--show-session-key
Display the session key used for one message. See
--override-session-key for the counterpart of this option.

We think that Key Escrow is a Bad Thing; however the user
should have the freedom to decide whether to go to prison or
to reveal the content of one specific message without
compromising all messages ever encrypted for one secret key.

You can also use this option if you receive an encrypted
message which is abusive or offensive, to prove to the
administrators of the messaging system that the ciphertext
transmitted corresponds to an inappropriate plaintext so they
can take action against the offending user.


--override-session-key string
--override-session-key-fd fd
Don't use the public key but the session key string respective
the session key taken from the first line read from file
descriptor fd. The format of this string is the same as the
one printed by --show-session-key. This option is normally not
used but comes handy in case someone forces you to reveal the
content of an encrypted message; using this option you can do
this without handing out the secret key. Note that using
--override-session-key may reveal the session key to all local
users via the global process table. Often it is useful to
combine this option with --no-keyring.


--ask-sig-expire
--no-ask-sig-expire
When making a data signature, prompt for an expiration time.
If this option is not specified, the expiration time set via
--default-sig-expire is used. --no-ask-sig-expire disables
this option.


--default-sig-expire
The default expiration time to use for signature expiration.
Valid values are "0" for no expiration, a number followed by
the letter d (for days), w (for weeks), m (for months), or y
(for years) (for example "2m" for two months, or "5y" for five
years), or an absolute date in the form YYYY-MM-DD. Defaults
to "0".


--ask-cert-expire
--no-ask-cert-expire
When making a key signature, prompt for an expiration time. If
this option is not specified, the expiration time set via
--default-cert-expire is used. --no-ask-cert-expire disables
this option.


--default-cert-expire
The default expiration time to use for key signature
expiration. Valid values are "0" for no expiration, a number
followed by the letter d (for days), w (for weeks), m (for
months), or y (for years) (for example "2m" for two months, or
"5y" for five years), or an absolute date in the form YYYY-MM-
DD. Defaults to "0".


--default-new-key-algo string
This option can be used to change the default algorithms for
key generation. The string is similar to the arguments
required for the command --quick-add-key but slightly
different. For example the current default of
"rsa2048/cert,sign+rsa2048/encr" (or "rsa3072") can be changed
to the value of what we currently call future default, which
is "ed25519/cert,sign+cv25519/encr". You need to consult the
source code to learn the details. Note that the advanced key
generation commands can always be used to specify a key
algorithm directly.


--force-sign-key
This option modifies the behaviour of the commands
--quick-sign-key, --quick-lsign-key, and the "sign" sub-
commands of --edit-key by forcing the creation of a key
signature, even if one already exists.


--forbid-gen-key
This option is intended for use in the global config file to
disallow the use of generate key commands. Those commands
will then fail with the error code for Not Enabled.


--allow-secret-key-import
This is an obsolete option and is not used anywhere.


--allow-multiple-messages

--no-allow-multiple-messages
Allow processing of multiple OpenPGP messages contained in a
single file or stream. Some programs that call GPG are not
prepared to deal with multiple messages being processed
together, so this option defaults to no. Note that versions
of GPG prior to 1.4.7 always allowed multiple messages.
Future versions of GnUPG will remove this option.

Warning: Do not use this option unless you need it as a
temporary workaround!


--enable-special-filenames
This option enables a mode in which filenames of the form
`-&n', where n is a non-negative decimal number, refer to the
file descriptor n and not to a file with that name.


--no-expensive-trust-checks
Experimental use only.


--preserve-permissions
Don't change the permissions of a secret keyring back to user
read/write only. Use this option only if you really know what
you are doing.


--default-preference-list string
Set the list of default preferences to string. This preference
list is used for new keys and becomes the default for
"setpref" in the edit menu.


--default-keyserver-url name
Set the default keyserver URL to name. This keyserver will be
used as the keyserver URL when writing a new self-signature on
a key, which includes key generation and changing preferences.


--list-config
Display various internal configuration parameters of GnuPG.
This option is intended for external programs that call GnuPG
to perform tasks, and is thus not generally useful. See the
file `doc/DETAILS' in the source distribution for the details
of which configuration items may be listed. --list-config is
only usable with --with-colons set.


--list-gcrypt-config
Display various internal configuration parameters of
Libgcrypt.


--gpgconf-list
This command is similar to --list-config but in general only
internally used by the gpgconf tool.


--gpgconf-test
This is more or less dummy action. However it parses the
configuration file and returns with failure if the
configuration file would prevent gpg2 from startup. Thus it
may be used to run a syntax check on the configuration file.

Deprecated options

--show-photos
--no-show-photos
Causes --list-keys, --list-signatures, --list-public-keys,
--list-secret-keys, and verifying a signature to also display
the photo ID attached to the key, if any. See also
--photo-viewer. These options are deprecated. Use
--list-options [no-]show-photos and/or --verify-options
[no-]show-photos instead.


--show-keyring
Display the keyring name at the head of key listings to show
which keyring a given key resides on. This option is
deprecated: use --list-options [no-]show-keyring instead.


--always-trust
Identical to --trust-model always. This option is deprecated.


--show-notation
--no-show-notation
Show signature notations in the --list-signatures or
--check-signatures listings as well as when verifying a
signature with a notation in it. These options are deprecated.
Use --list-options [no-]show-notation and/or --verify-options
[no-]show-notation instead.


--show-policy-url
--no-show-policy-url
Show policy URLs in the --list-signatures or
--check-signatures listings as well as when verifying a
signature with a policy URL in it. These options are
deprecated. Use --list-options [no-]show-policy-url and/or
--verify-options [no-]show-policy-url instead.

EXAMPLES

gpg -se -r Bob file
sign and encrypt for user Bob


gpg --clear-sign file
make a cleartext signature


gpg -sb file
make a detached signature


gpg -u 0x12345678 -sb file
make a detached signature with the key 0x12345678


gpg --list-keys user_ID
show keys


gpg --fingerprint user_ID
show fingerprint


gpg --verify pgpfile
gpg --verify sigfile [datafile]
Verify the signature of the file but do not output the data
unless requested. The second form is used for detached
signatures, where sigfile is the detached signature (either
ASCII armored or binary) and datafile are the signed data; if
this is not given, the name of the file holding the signed
data is constructed by cutting off the extension (".asc" or
".sig") of sigfile or by asking the user for the filename. If
the option --output is also used the signed data is written to
the file specified by that option; use - to write the signed
data to stdout.

HOW TO SPECIFY A USER ID

There are different ways to specify a user ID to GnuPG. Some of them
are only valid for gpg others are only good for gpgsm. Here is the
entire list of ways to specify a key:


By key Id.
This format is deduced from the length of the string and its
content or 0x prefix. The key Id of an X.509 certificate are
the low 64 bits of its SHA-1 fingerprint. The use of key Ids
is just a shortcut, for all automated processing the
fingerprint should be used.

When using gpg an exclamation mark (!) may be appended to
force using the specified primary or secondary key and not to
try and calculate which primary or secondary key to use.

The last four lines of the example give the key ID in their
long form as internally used by the OpenPGP protocol. You can
see the long key ID using the option --with-colons.

234567C4
0F34E556E
01347A56A
0xAB123456

234AABBCC34567C4
0F323456784E56EAB
01AB3FED1347A5612
0x234AABBCC34567C4


By fingerprint.
This format is deduced from the length of the string and its
content or the 0x prefix. Note, that only the 20 byte version
fingerprint is available with gpgsm (i.e. the SHA-1 hash of
the certificate).

When using gpg an exclamation mark (!) may be appended to
force using the specified primary or secondary key and not to
try and calculate which primary or secondary key to use.

The best way to specify a key Id is by using the fingerprint.
This avoids any ambiguities in case that there are duplicated
key IDs.

1234343434343434C434343434343434
123434343434343C3434343434343734349A3434
0E12343434343434343434EAB3484343434343434
0xE12343434343434343434EAB3484343434343434


gpgsm also accepts colons between each pair of hexadecimal digits
because this is the de-facto standard on how to present X.509
fingerprints. gpg also allows the use of the space separated SHA-1
fingerprint as printed by the key listing commands.


By exact match on OpenPGP user ID.
This is denoted by a leading equal sign. It does not make
sense for X.509 certificates.

=Heinrich Heine <heinrichh@uni-duesseldorf.de>


By exact match on an email address.
This is indicated by enclosing the email address in the usual
way with left and right angles.

<heinrichh@uni-duesseldorf.de>


By partial match on an email address.
This is indicated by prefixing the search string with an @.
This uses a substring search but considers only the mail
address (i.e. inside the angle brackets).

@heinrichh


By exact match on the subject's DN.
This is indicated by a leading slash, directly followed by the
RFC-2253 encoded DN of the subject. Note that you can't use
the string printed by gpgsm --list-keys because that one has
been reordered and modified for better readability; use
--with-colons to print the raw (but standard escaped) RFC-2253
string.

/CN=Heinrich Heine,O=Poets,L=Paris,C=FR


By exact match on the issuer's DN.
This is indicated by a leading hash mark, directly followed by
a slash and then directly followed by the RFC-2253 encoded DN
of the issuer. This should return the Root cert of the
issuer. See note above.

#/CN=Root Cert,O=Poets,L=Paris,C=FR


By exact match on serial number and issuer's DN.
This is indicated by a hash mark, followed by the hexadecimal
representation of the serial number, then followed by a slash
and the RFC-2253 encoded DN of the issuer. See note above.

#4F03/CN=Root Cert,O=Poets,L=Paris,C=FR


By keygrip.
This is indicated by an ampersand followed by the 40 hex
digits of a keygrip. gpgsm prints the keygrip when using the
command --dump-cert.

&D75F22C3F86E355877348498CDC92BD21010A480


By substring match.
This is the default mode but applications may want to
explicitly indicate this by putting the asterisk in front.
Match is not case sensitive.

Heine
*Heine


. and + prefixes
These prefixes are reserved for looking up mails anchored at
the end and for a word search mode. They are not yet
implemented and using them is undefined.


Please note that we have reused the hash mark identifier which
was used in old GnuPG versions to indicate the so called
local-id. It is not anymore used and there should be no
conflict when used with X.509 stuff.

Using the RFC-2253 format of DNs has the drawback that it is
not possible to map them back to the original encoding,
however we don't have to do this because our key database
stores this encoding as meta data.

FILTER EXPRESSIONS

The options --import-filter and --export-filter use expressions with
this syntax (square brackets indicate an optional part and curly
braces a repetition, white space between the elements are allowed):

[lc] {[{flag}] PROPNAME op VALUE [lc]}

The name of a property (PROPNAME) may only consist of letters, digits
and underscores. The description for the filter type describes which
properties are defined. If an undefined property is used it
evaluates to the empty string. Unless otherwise noted, the VALUE
must always be given and may not be the empty string. No quoting is
defined for the value, thus the value may not contain the strings &&
or ||, which are used as logical connection operators. The flag --
can be used to remove this restriction.

Numerical values are computed as long int; standard C notation
applies. lc is the logical connection operator; either && for a
conjunction or || for a disjunction. A conjunction is assumed at the
begin of an expression. Conjunctions have higher precedence than
disjunctions. If VALUE starts with one of the characters used in any
op a space after the op is required.


The supported operators (op) are:


=~ Substring must match.


!~ Substring must not match.


= The full string must match.


<> The full string must not match.


== The numerical value must match.


!= The numerical value must not match.


<= The numerical value of the field must be LE than the value.


< The numerical value of the field must be LT than the value.


> The numerical value of the field must be GT than the value.


>= The numerical value of the field must be GE than the value.


-le The string value of the field must be less or equal than the
value.


-lt The string value of the field must be less than the value.


-gt The string value of the field must be greater than the value.


-ge The string value of the field must be greater or equal than
the value.


-n True if value is not empty (no value allowed).


-z True if value is empty (no value allowed).


-t Alias for "PROPNAME != 0" (no value allowed).


-f Alias for "PROPNAME == 0" (no value allowed).


Values for flag must be space separated. The supported flags are:


-- VALUE spans to the end of the expression.

-c The string match in this part is done case-sensitive.

-t Leading and trailing spaces are not removed from VALUE. The
optional single space after op is here required.

The filter options concatenate several specifications for a filter of
the same type. For example the four options in this example:

--import-filter keep-uid="uid =~ Alfa"
--import-filter keep-uid="&& uid !~ Test"
--import-filter keep-uid="|| uid =~ Alpha"
--import-filter keep-uid="uid !~ Test"


which is equivalent to

--import-filter \
keep-uid="uid =~ Alfa" && uid !~ Test" || uid =~ Alpha" && "uid !~ Test"

imports only the user ids of a key containing the strings "Alfa" or
"Alpha" but not the string "test".

TRUST VALUES

Trust values are used to indicate ownertrust and validity of keys and
user IDs. They are displayed with letters or strings:


-
unknown
No ownertrust assigned / not yet calculated.


e
expired

Trust calculation has failed; probably due to an expired key.


q
undefined, undef
Not enough information for calculation.


n
never Never trust this key.


m
marginal
Marginally trusted.


f
full Fully trusted.


u
ultimate
Ultimately trusted.


r
revoked
For validity only: the key or the user ID has been revoked.


?
err The program encountered an unknown trust value.

FILES

There are a few configuration files to control certain aspects of
gpg2's operation. Unless noted, they are expected in the current home
directory (see: [option --homedir]).


gpg.conf
This is the standard configuration file read by gpg2 on
startup. It may contain any valid long option; the leading
two dashes may not be entered and the option may not be
abbreviated. This default name may be changed on the command
line (see: [gpg-option --options]). You should backup this
file.


Note that on larger installations, it is useful to put predefined
files into the directory `/usr/etc/skel/.gnupg' so that newly created
users start up with a working configuration. For existing users a
small helper script is provided to create these files (see:
[addgnupghome]).

For internal purposes gpg2 creates and maintains a few other files;
They all live in the current home directory (see: [option
--homedir]). Only the gpg2 program may modify these files.


~/.gnupg
This is the default home directory which is used if neither
the environment variable GNUPGHOME nor the option --homedir is
given.


~/.gnupg/pubring.gpg
The public keyring using a legacy format. You should backup
this file.

If this file is not available, gpg defaults to the new keybox
format and creates a file `pubring.kbx' unless that file
already exists in which case that file will also be used for
OpenPGP keys.

Note that in the case that both files, `pubring.gpg' and
`pubring.kbx' exists but the latter has no OpenPGP keys, the
legacy file `pubring.gpg' will be used. Take care: GnuPG
versions before 2.1 will always use the file `pubring.gpg'
because they do not know about the new keybox format. In the
case that you have to use GnuPG 1.4 to decrypt archived data
you should keep this file.


~/.gnupg/pubring.gpg.lock
The lock file for the public keyring.


~/.gnupg/pubring.kbx
The public keyring using the new keybox format. This file is
shared with gpgsm. You should backup this file. See above
for the relation between this file and it predecessor.

To convert an existing `pubring.gpg' file to the keybox
format, you first backup the ownertrust values, then rename
`pubring.gpg' to `publickeys.backup', so it won't be
recognized by any GnuPG version, run import, and finally
restore the ownertrust values:

$ cd ~/.gnupg
$ gpg --export-ownertrust >otrust.lst
$ mv pubring.gpg publickeys.backup
$ gpg --import-options restore --import publickeys.backups
$ gpg --import-ownertrust otrust.lst


~/.gnupg/pubring.kbx.lock
The lock file for `pubring.kbx'.


~/.gnupg/secring.gpg
The legacy secret keyring as used by GnuPG versions before
2.1. It is not used by GnuPG 2.1 and later. You may want to
keep it in case you have to use GnuPG 1.4 to decrypt archived
data.


~/.gnupg/secring.gpg.lock
The lock file for the legacy secret keyring.


~/.gnupg/.gpg-v21-migrated
File indicating that a migration to GnuPG 2.1 has been done.


~/.gnupg/trustdb.gpg
The trust database. There is no need to backup this file; it
is better to backup the ownertrust values (see: [option
--export-ownertrust]).


~/.gnupg/trustdb.gpg.lock
The lock file for the trust database.


~/.gnupg/random_seed
A file used to preserve the state of the internal random pool.


~/.gnupg/openpgp-revocs.d/
This is the directory where gpg stores pre-generated
revocation certificates. The file name corresponds to the
OpenPGP fingerprint of the respective key. It is suggested to
backup those certificates and if the primary private key is
not stored on the disk to move them to an external storage
device. Anyone who can access theses files is able to revoke
the corresponding key. You may want to print them out. You
should backup all files in this directory and take care to
keep this backup closed away.


Operation is further controlled by a few environment variables:


HOME Used to locate the default home directory.


GNUPGHOME
If set directory used instead of "~/.gnupg".


GPG_AGENT_INFO
This variable is obsolete; it was used by GnuPG versions
before 2.1.


PINENTRY_USER_DATA
This value is passed via gpg-agent to pinentry. It is useful
to convey extra information to a custom pinentry.


COLUMNS
LINES Used to size some displays to the full size of the screen.


LANGUAGE
Apart from its use by GNU, it is used in the W32 version to
override the language selection done through the Registry. If
used and set to a valid and available language name (langid),
the file with the translation is loaded from
gpgdir/gnupg.nls/langid.mo. Here gpgdir is the directory out
of which the gpg binary has been loaded. If it can't be
loaded the Registry is tried and as last resort the native
Windows locale system is used.


GNUPG_BUILD_ROOT
This variable is only used by the regression test suite as a
helper under operating systems without proper support to
figure out the name of a process' text file.


GNUPG_EXEC_DEBUG_FLAGS
This variable allows to enable diagnostics for process
management. A numeric decimal value is expected. Bit 0
enables general diagnostics, bit 1 enables certain warnings on
Windows.


When calling the gpg-agent component gpg2 sends a set of environment
variables to gpg-agent. The names of these variables can be listed
using the command:

gpg-connect-agent 'getinfo std_env_names' /bye | awk '$1=="D" {print $2}'

BUGS

On older systems this program should be installed as setuid(root).
This is necessary to lock memory pages. Locking memory pages prevents
the operating system from writing memory pages (which may contain
passphrases or other sensitive material) to disk. If you get no
warning message about insecure memory your operating system supports
locking without being root. The program drops root privileges as soon
as locked memory is allocated.

Note also that some systems (especially laptops) have the ability to
``suspend to disk'' (also known as ``safe sleep'' or ``hibernate'').
This writes all memory to disk before going into a low power or even
powered off mode. Unless measures are taken in the operating system
to protect the saved memory, passphrases or other sensitive material
may be recoverable from it later.

Before you report a bug you should first search the mailing list
archives for similar problems and second check whether such a bug has
already been reported to our bug tracker at https://bugs.gnupg.org.

SEE ALSO

gpgv(1), gpgsm(1), gpg-agent(1)

The full documentation for this tool is maintained as a Texinfo
manual. If GnuPG and the info program are properly installed at your
site, the command

info gnupg

should give you access to the complete manual including a menu
structure and an index.

GnuPG 2.2.43 2024-03-04 GPG2(1)