des_crypt

DES_CRYPT(3)               Linux Programmer's Manual              DES_CRYPT(3)



NAME
       des_crypt, ecb_crypt, cbc_crypt, des_setparity, DES_FAILED - fast DES
       encryption

SYNOPSIS
       #include <rpc/des_crypt.h>

       int ecb_crypt(char *key, char *data, unsigned datalen,
                     unsigned mode);

       int cbc_crypt(char *key, char *data, unsigned datalen,
                     unsigned mode, char *ivec);

       void des_setparity(char *key);

       int DES_FAILED(int status);

DESCRIPTION
       ecb_crypt() and cbc_crypt() implement the NBS DES (Data Encryption
       Standard).  These routines are faster and more general purpose than
       crypt(3).  They also are able to utilize DES hardware if it is
       available.  ecb_crypt() encrypts in ECB (Electronic Code Book) mode,
       which encrypts blocks of data independently.  cbc_crypt() encrypts in
       CBC (Cipher Block Chaining) mode, which chains together successive
       blocks.  CBC mode protects against insertions, deletions and
       substitutions of blocks.  Also, regularities in the clear text will not
       appear in the cipher text.

       Here is how to use these routines.  The first argument, key, is the
       8-byte encryption key with parity.  To set the key's parity, which for
       DES is in the low bit of each byte, use des_setparity().  The second
       argument, data, contains the data to be encrypted or decrypted.  The
       third argument, datalen, is the length in bytes of data, which must be
       a multiple of 8.  The fourth argument, mode, is formed by ORing
       together some things.  For the encryption direction OR in either
       DES_ENCRYPT or DES_DECRYPT.  For software versus hardware encryption,
       OR in either DES_HW or DES_SW.  If DES_HW is specified, and there is no
       hardware, then the encryption is performed in software and the routine
       returns DESERR_NOHWDEVICE.  For cbc_crypt(), the argument ivec is the
       8-byte initialization vector for the chaining.  It is updated to the
       next initialization vector upon return.

RETURN VALUE
       DESERR_NONE         No error.
       DESERR_NOHWDEVICE   Encryption succeeded, but done in software instead
                           of the requested hardware.
       DESERR_HWERROR      An error occurred in the hardware or driver.
       DESERR_BADPARAM     Bad argument to routine.

       Given a result status stat, the macro DES_FAILED(stat) is false only
       for the first two statuses.

VERSIONS
       These functions are present in glibc 2.1 and later.

VERSIONS
       Because they employ the DES block cipher, which is no longer considered
       secure, ecb_crypt(), ecb_crypt(), crypt_r(), and des_setparity() were
       removed in glibc 2.28.  Applications should switch to a modern
       cryptography library, such as libgcrypt.

ATTRIBUTES
       For an explanation of the terms used in this section, see
       attributes(7).

       ┌──────────────────────────┬───────────────┬─────────┐
       │Interface                 Attribute     Value   │
       ├──────────────────────────┼───────────────┼─────────┤
       │ecb_crypt(), cbc_crypt(), │ Thread safety │ MT-Safe │
       │des_setparity()           │               │         │
       └──────────────────────────┴───────────────┴─────────┘
CONFORMING TO
       4.3BSD.  Not in POSIX.1.

SEE ALSO
       des(1), crypt(3), xcrypt(3)

COLOPHON
       This page is part of release 5.01 of the Linux man-pages project.  A
       description of the project, information about reporting bugs, and the
       latest version of this page, can be found at
       https://www.kernel.org/doc/man-pages/.



                                  2019-03-06                      DES_CRYPT(3)