des_crypt(3) — Linux manual page


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

NAME         top

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

SYNOPSIS         top

       #include <rpc/des_crypt.h>

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

       void des_setparity(char *key);

       int DES_FAILED(int status);

DESCRIPTION         top

       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         top

              No error.

              Encryption succeeded, but done in software instead of the
              requested hardware.

              An error occurred in the hardware or driver.

              Bad argument to routine.

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

VERSIONS         top

       These functions were added to glibc in version 2.1.

       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         top

       For an explanation of the terms used in this section, see

       │Interface                             Attribute     Value   │
       │ecb_crypt(), cbc_crypt(),             │ Thread safety │ MT-Safe │
       │des_setparity()                       │               │         │

CONFORMING TO         top

       4.3BSD.  Not in POSIX.1.

SEE ALSO         top

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

COLOPHON         top

       This page is part of release 5.13 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

                               2021-03-22                   DES_CRYPT(3)

Pages that refer to this page: encrypt(3)xcrypt(3)