CRYPT(3C) Standard C Library Functions CRYPT(3C)


NAME


crypt - string encoding function

SYNOPSIS


#include <crypt.h>

char *crypt(const char *key, const char *salt);


Standard conforming


#include <unistd.h>

char *crypt(const char *key, const char *salt);


DESCRIPTION


The crypt() function encodes strings suitable for secure storage as
passwords. It generates the password hash given the key and salt.


The key argument is the plain text password to be encrypted.


If the first character of salt is "$", crypt() uses crypt.conf(4) to
determine which shared module to load for the encryption algorithm. The
algorithm name crypt() uses to search in crypt.conf is the string between
the first and second "$", or between the first "$" and first "," if a ","
comes before the second "$".


If the first character of salt is not "$", the algorithm described on
crypt_unix(5) is used.

RETURN VALUES


Upon successful completion, crypt() returns a pointer to the encoded
string. Otherwise it returns a null pointer and sets errno to indicate
the error.


The return value points to static data that is overwritten by each call.

ERRORS


The crypt() function will fail if:

EINVAL
An entry in crypt.conf is invalid.


ELIBACC
The required shared library was not found.


ENOMEM
There is insufficient memory to generate the hash.


ENOSYS
The functionality is not supported on this system.


USAGE


The values returned by this function might not be portable among
standard-conforming systems. See standards(5).


Applications should not use crypt() to store or verify user passwords but
should use the functions described on pam(3PAM) instead.

ATTRIBUTES


See attributes(5) for descriptions of the following attributes:


+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Interface Stability | Standard |
+--------------------+-----------------+
|MT-Level | MT-Safe |
+--------------------+-----------------+

SEE ALSO


passwd(1), crypt_genhash_impl(3C), crypt_gensalt(3C),
crypt_gensalt_impl(3C), getpassphrase(3C), pam(3PAM), passwd(4),
policy.conf(4), attributes(5), crypt_unix(5), standards(5)


September 28, 2004 CRYPT(3C)