DES_CRYPT(3) BSD Library Functions Manual DES_CRYPT(3)
NAME
des_crypt, ecb_crypt, cbc_crypt, des_setparity — 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);
DESCRIPTION
The ecb_crypt() and cbc_crypt() functions implement the NBS DES (Data En-
cryption Standard). These routines are faster and more general purpose
than crypt(3). They also are able to utilize DES hardware if it is
available. The ecb_crypt() function encrypts in ECB (Electronic Code
Book) mode, which encrypts blocks of data independently. The cbc_crypt()
function encrypts in CBC (Cipher Block Chaining) mode, which chains to-
gether successive blocks. CBC mode protects against insertions, dele-
tions 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 ar-
gument, data, contains the data to be encrypted or decrypted. The third
argument, datalen, is the length in bytes of data, which must be a multi-
ple of 8. The fourth argument, mode, is formed by OR'ing 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 ivec argument is the 8-byte ini-
tialization vector for the chaining. It is updated to the next initial-
ization vector upon return.
ERRORS
[DESERR_NONE] No error.
[DESERR_NOHWDEVICE] Encryption succeeded, but done in software instead
of the requested hardware.
[DESERR_HWERR] 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.
AVAILABILITY
The ecb_crypt(), cbc_crypt(), and des_setparity() functions are part of
libtirpc.
SEE ALSO
crypt(3)
RESTRICTIONS
These routines are not available in RPCSRC 4.0. This information is pro-
vided to describe the DES interface expected by Secure RPC.
BSD October 6, 1987 BSD
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