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

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

       #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);

       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  avail-
       able.   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 to-
       gether some things.  For the encryption direction OR in either  DES_EN-
       CRYPT  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 hard-
       ware,  then the encryption is performed in software and the routine re-
       turns 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.

       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.

       These functions are present in glibc 2.1 and later.

       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 cryptog-
       raphy library, such as libgcrypt.

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

       |Interface                 | Attribute     | Value   |
       |ecb_crypt(), cbc_crypt(), | Thread safety | MT-Safe |
       |des_setparity()           |               |         |
       4.3BSD.  Not in POSIX.1.

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

       This  page  is  part of release 5.05 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

                                  2019-03-06                      DES_CRYPT(3)
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