Tribblix: manual page: isencrypt.3gen

ISENCRYPT(3GEN) String Pattern-Matching Library Functions ISENCRYPT(3GEN)

NAME

isencrypt - determine whether a buffer of characters is encrypted

SYNOPSIS

cc [flag]... [file]... -lgen [library]...

#include <libgen.h>

int isencrypt(const char *fbuf, size_t ninbuf);

DESCRIPTION

isencrypt() uses heuristics to determine whether a buffer of
characters is encrypted. It requires two arguments: a pointer to an
array of characters and the number of characters in the buffer.

isencrypt() assumes that the file is not encrypted if all the
characters in the first block are ASCII characters. If there are
non-ASCII characters in the first ninbuf characters, and if the
setlocale() LC_CTYPE category is set to C or ascii, isencrypt()
assumes that the buffer is encrypted

If the LC_CTYPE category is set to a value other than C or ascii,
then isencrypt() uses a combination of heuristics to determine if the
buffer is encrypted. If ninbuf has at least 64 characters, a chi-
square test is used to determine if the bytes in the buffer have a
uniform distribution; if it does, then isencrypt() assumes the buffer
is encrypted. If the buffer has less than 64 characters, a check is
made for null characters and a terminating new-line to determine
whether the buffer is encrypted.

RETURN VALUES

If the buffer is encrypted, 1 is returned; otherwise, zero is
returned.

ATTRIBUTES

NOTES