DNSSEC-KEYGEN(1) BIND 9 DNSSEC-KEYGEN(1)

NAME

dnssec-keygen - DNSSEC key generation tool

SYNOPSIS

dnssec-keygen [-3] [-A date/offset] [-a algorithm] [-b keysize] [-C]
[-c class] [-D date/offset] [-d bits] [-D sync date/offset] [-E
engine] [-f flag] [-G] [-g generator] [-h] [-I date/offset] [-i
interval] [-K directory] [-k policy] [-L ttl] [-l file] [-n nametype]
[-P date/offset] [-P sync date/offset] [-p protocol] [-q] [-R
date/offset] [-S key] [-s strength] [-T rrtype] [-t type] [-V] [-v
level] {name}

DESCRIPTION

dnssec-keygen generates keys for DNSSEC (Secure DNS), as defined in
RFC 2535 and RFC 4034.

The name of the key is specified on the command line. For DNSSEC
keys, this must match the name of the zone for which the key is being
generated.

OPTIONS

-3 This option uses an NSEC3-capable algorithm to generate a
DNSSEC key. If this option is used with an algorithm that has
both NSEC and NSEC3 versions, then the NSEC3 version is
selected; for example, dnssec-keygen -3 -a RSASHA1 specifies
the NSEC3RSASHA1 algorithm.

-a algorithm
This option selects the cryptographic algorithm. For DNSSEC
keys, the value of algorithm must be one of RSASHA1,
NSEC3RSASHA1, RSASHA256, RSASHA512, ECDSAP256SHA256,
ECDSAP384SHA384, ED25519, or ED448. For TKEY, the value must
be DH (Diffie-Hellman); specifying this value automatically
sets the -T KEY option as well.

These values are case-insensitive. In some cases,
abbreviations are supported, such as ECDSA256 for
ECDSAP256SHA256 and ECDSA384 for ECDSAP384SHA384. If RSASHA1
is specified along with the -3 option, NSEC3RSASHA1 is used
instead.

This parameter must be specified except when using the -S
option, which copies the algorithm from the predecessor key.

In prior releases, HMAC algorithms could be generated for use
as TSIG keys, but that feature was removed in BIND 9.13.0. Use
tsig-keygen to generate TSIG keys.

-b keysize
This option specifies the number of bits in the key. The
choice of key size depends on the algorithm used: RSA keys
must be between 1024 and 4096 bits; Diffie-Hellman keys must
be between 128 and 4096 bits. Elliptic curve algorithms do not
need this parameter.

If the key size is not specified, some algorithms have
pre-defined defaults. For example, RSA keys for use as DNSSEC
zone-signing keys have a default size of 1024 bits; RSA keys
for use as key-signing keys (KSKs, generated with -f KSK)
default to 2048 bits.

-C This option enables compatibility mode, which generates an
old-style key, without any timing metadata. By default,
dnssec-keygen includes the key's creation date in the metadata
stored with the private key; other dates may be set there as
well, including publication date, activation date, etc. Keys
that include this data may be incompatible with older versions
of BIND; the -C option suppresses them.

-c class
This option indicates that the DNS record containing the key
should have the specified class. If not specified, class IN is
used.

-d bits
This option specifies the key size in bits. For the algorithms
RSASHA1, NSEC3RSASA1, RSASHA256, and RSASHA512 the key size
must be between 1024 and 4096 bits; DH size is between 128 and
4096 bits. This option is ignored for algorithms
ECDSAP256SHA256, ECDSAP384SHA384, ED25519, and ED448.

-E engine
This option specifies the cryptographic hardware to use, when
applicable.

When BIND 9 is built with OpenSSL, this needs to be set to the
OpenSSL engine identifier that drives the cryptographic
accelerator or hardware service module (usually pkcs11).

-f flag
This option sets the specified flag in the flag field of the
KEY/DNSKEY record. The only recognized flags are KSK
(Key-Signing Key) and REVOKE.

-G This option generates a key, but does not publish it or sign
with it. This option is incompatible with -P and -A.

-g generator
This option indicates the generator to use if generating a
Diffie-Hellman key. Allowed values are 2 and 5. If no
generator is specified, a known prime from RFC 2539 is used if
possible; otherwise the default is 2.

-h This option prints a short summary of the options and
arguments to dnssec-keygen.

-K directory
This option sets the directory in which the key files are to
be written.

-k policy
This option creates keys for a specific dnssec-policy. If a
policy uses multiple keys, dnssec-keygen generates multiple
keys. This also creates a ".state" file to keep track of the
key state.

This option creates keys according to the dnssec-policy
configuration, hence it cannot be used at the same time as
many of the other options that dnssec-keygen provides.

-L ttl This option sets the default TTL to use for this key when it
is converted into a DNSKEY RR. This is the TTL used when the
key is imported into a zone, unless there was already a DNSKEY
RRset in place, in which case the existing TTL takes
precedence. If this value is not set and there is no existing
DNSKEY RRset, the TTL defaults to the SOA TTL. Setting the
default TTL to 0 or none is the same as leaving it unset.

-l file
This option provides a configuration file that contains a
dnssec-policy statement (matching the policy set with -k).

-n nametype
This option specifies the owner type of the key. The value of
nametype must either be ZONE (for a DNSSEC zone key
(KEY/DNSKEY)), HOST or ENTITY (for a key associated with a
host (KEY)), USER (for a key associated with a user (KEY)), or
OTHER (DNSKEY). These values are case-insensitive. The default
is ZONE for DNSKEY generation.

-p protocol
This option sets the protocol value for the generated key, for
use with -T KEY. The protocol is a number between 0 and 255.
The default is 3 (DNSSEC). Other possible values for this
argument are listed in RFC 2535 and its successors.

-q This option sets quiet mode, which suppresses unnecessary
output, including progress indication. Without this option,
when dnssec-keygen is run interactively to generate an RSA or
DSA key pair, it prints a string of symbols to stderr
indicating the progress of the key generation. A . indicates
that a random number has been found which passed an initial
sieve test; + means a number has passed a single round of the
Miller-Rabin primality test; and a space ( ) means that the
number has passed all the tests and is a satisfactory key.

-S key This option creates a new key which is an explicit successor
to an existing key. The name, algorithm, size, and type of
the key are set to match the existing key. The activation date
of the new key is set to the inactivation date of the existing
one. The publication date is set to the activation date minus
the prepublication interval, which defaults to 30 days.

-s strength
This option specifies the strength value of the key. The
strength is a number between 0 and 15, and currently has no
defined purpose in DNSSEC.

-T rrtype
This option specifies the resource record type to use for the
key. rrtype must be either DNSKEY or KEY. The default is
DNSKEY when using a DNSSEC algorithm, but it can be overridden
to KEY for use with SIG(0).

-t type
This option indicates the type of the key for use with -T KEY.
type must be one of AUTHCONF, NOAUTHCONF, NOAUTH, or NOCONF.
The default is AUTHCONF. AUTH refers to the ability to
authenticate data, and CONF to the ability to encrypt data.

-V This option prints version information.

-v level
This option sets the debugging level.

TIMING OPTIONS

Dates can be expressed in the format YYYYMMDD or YYYYMMDDHHMMSS
(which is the format used inside key files), or 'Day Mon DD HH:MM:SS
YYYY' (as printed by dnssec-settime -p), or UNIX epoch time (as
printed by dnssec-settime -up), or the literal now.

The argument can be followed by + or - and an offset from the given
time. The literal now can be omitted before an offset. The offset can
be followed by one of the suffixes y, mo, w, d, h, or mi, so that it
is computed in years (defined as 365 24-hour days, ignoring leap
years), months (defined as 30 24-hour days), weeks, days, hours, or
minutes, respectively. Without a suffix, the offset is computed in
seconds.

To unset a date, use none, never, or unset.

-P date/offset
This option sets the date on which a key is to be published to
the zone. After that date, the key is included in the zone but
is not used to sign it. If not set, and if the -G option has
not been used, the default is the current date.

sync date/offset
This option sets the date on which CDS and CDNSKEY
records that match this key are to be published to the
zone.

-A date/offset
This option sets the date on which the key is to be activated.
After that date, the key is included in the zone and used to
sign it. If not set, and if the -G option has not been used,
the default is the current date. If set, and -P is not set,
the publication date is set to the activation date minus the
prepublication interval.

-R date/offset
This option sets the date on which the key is to be revoked.
After that date, the key is flagged as revoked. It is included
in the zone and is used to sign it.

-I date/offset
This option sets the date on which the key is to be retired.
After that date, the key is still included in the zone, but it
is not used to sign it.

-D date/offset
This option sets the date on which the key is to be deleted.
After that date, the key is no longer included in the zone.
(However, it may remain in the key repository.)

sync date/offset
This option sets the date on which the CDS and CDNSKEY
records that match this key are to be deleted.

-i interval
This option sets the prepublication interval for a key. If
set, then the publication and activation dates must be
separated by at least this much time. If the activation date
is specified but the publication date is not, the publication
date defaults to this much time before the activation date;
conversely, if the publication date is specified but not the
activation date, activation is set to this much time after
publication.

If the key is being created as an explicit successor to
another key, then the default prepublication interval is 30
days; otherwise it is zero.

As with date offsets, if the argument is followed by one of
the suffixes y, mo, w, d, h, or mi, the interval is measured
in years, months, weeks, days, hours, or minutes,
respectively. Without a suffix, the interval is measured in
seconds.

GENERATED KEYS

When dnssec-keygen completes successfully, it prints a string of the
form Knnnn.+aaa+iiiii to the standard output. This is an
identification string for the key it has generated.

+o nnnn is the key name.

+o aaa is the numeric representation of the algorithm.

+o iiiii is the key identifier (or footprint).

dnssec-keygen creates two files, with names based on the printed
string. Knnnn.+aaa+iiiii.key contains the public key, and
Knnnn.+aaa+iiiii.private contains the private key.

The .key file contains a DNSKEY or KEY record. When a zone is being
signed by named or dnssec-signzone -S, DNSKEY records are included
automatically. In other cases, the .key file can be inserted into a
zone file manually or with an $INCLUDE statement.

The .private file contains algorithm-specific fields. For obvious
security reasons, this file does not have general read permission.

EXAMPLE

To generate an ECDSAP256SHA256 zone-signing key for the zone
example.com, issue the command:

dnssec-keygen -a ECDSAP256SHA256 example.com

The command prints a string of the form:

Kexample.com.+013+26160

In this example, dnssec-keygen creates the files
Kexample.com.+013+26160.key and Kexample.com.+013+26160.private.

To generate a matching key-signing key, issue the command:

dnssec-keygen -a ECDSAP256SHA256 -f KSK example.com

SEE ALSO

dnssec-signzone(8), BIND 9 Administrator Reference Manual, RFC 2539,
RFC 2845, RFC 4034.

AUTHOR

Internet Systems Consortium

COPYRIGHT

2025, Internet Systems Consortium

9.18.34 2025-02-11 DNSSEC-KEYGEN(1)