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

       This  page  is  part of release 4.15 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/.

                                            2015-03-02                               DES_CRYPT(3)