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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 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
       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 substi‐
       tutions 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(), des_setparity()                                                                                             │ Thread safety │ MT-Safe │
       └──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┴───────────────┴─────────┘

CONFORMING TO
       4.3BSD.  Not in POSIX.1.

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

                                                                               2021-03-22                                                                   DES_CRYPT(3)