Then determines how the rest of the password string is $ id$ salt$ encrypted id identifies the encryption method used instead of DES and this If salt is a character string starting with the characters "$ id$"įollowed by a string optionally terminated by "$", then the The glibc version of this function supports additional encryption Otherwise libxcrypt is an ABI-compatible drop-in replacement. When recompiling applications in suchĭistributions, the programmer must detect if _XOPEN_CRYPT is notĪvailable and include for the function prototypes
May be the case if the downstream distribution has switched from _XOPEN_CRYPT is either not defined, or it is defined to -1 andĪvailability can be checked at run time with sysconf(3). If the interfaces are not available, then the symbolic constant POSIX.1-2008 XSI Options Group for Encryption and are optional. The crypt(), encrypt(3), and setkey(3) functions are part of the │ crypt() │ Thread safety │ MT-Unsafe race:crypt │ OnĮRRORS top EINVAL salt has the wrong format.ĮNOSYS The crypt() function was not implemented, probably becauseĮPERM /proc/sys/crypto/fips_enabled has a nonzero value, and anĪttempt was made to use a weak encryption type, such asįor an explanation of the terms used in this section, see On success, a pointer to the encrypted password is returned. To zero before the first call to crypt_r(). Other than allocating it, the only thing that theĬaller should do with this structure is to set data->initialized Pointed to by data is used to store result data and bookkeeping Good book on encryption and one of the widely available DESĬrypt_r() is a reentrant version of crypt(). If you are planning on using theĬrypt() interface for a cryptography project, don't do it: get a
The crypt() interface a very poor choice for anything other than The DES algorithm itself has a few quirks which make the use of Use of a passwd(1) program that checks for crackable passwordsĭuring the selection process is recommended. Selection should, at minimum, avoid common words and names. Software, such as crack(1), isĪvailable which will search the portion of this key space that is Exhaustive searches of this key space are possible using Warning: the key space consists of 2**56 equal 7.2e16 possible Points to static data whose content is overwritten by each call. Two characters represent the salt itself).
Sha512 crypt3 series#
Password, a series of 13 printable ASCII characters (the first The returned value points to the encrypted
This 56-bit key is used toĮncrypt repeatedly a constant string (usually a string consisting This string is used to perturb the algorithm in one of 4096īy taking the lowest 7 bits of each of the first eight characters Salt is a two-character string chosen from the set. (among other things) to discourage use of hardware It is based on theĭata Encryption Standard algorithm with variations intended SYNOPSIS top #include char *crypt(const char * key, const char * salt ) #include char *crypt_r(const char * key, const char * salt, struct crypt_data *restrict data ) įeature Test Macro Requirements for glibc (seeĭESCRIPTION top crypt() is the password encryption function.
Sha512 crypt3 manual#
CRYPT(3) Linux Programmer's Manual CRYPT(3) NAME topĬrypt, crypt_r - password and data encryption
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