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 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

       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 5.10 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/.

                                            2020-04-11                               DES_CRYPT(3)