Ubuntu Manpage: des_crypt, ecb_crypt, cbc_crypt, des_setparity, DES_FAILED

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.

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.

COLOPHON

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       information  about  reporting  bugs,  and  the  latest  version  of  this   page,   can   be   found   at
       https://www.kernel.org/doc/man-pages/.

                                                   2015-03-02                                       DES_CRYPT(3)