DES_CRYPT(3) BSD Library Functions Manual DES_CRYPT(3)NAME
des_crypt, ecb_crypt, cbc_crypt, des_setparity — fast DES encryption
LIBRARY
Standard C Library (libc, -lc)
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);
DESCRIPTIONecb_crypt() and cbc_crypt() implement the NBS DES (Data Encryption Stan‐
dard). 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 pro‐
tects 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 parameter, 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
parameter, data, contains the data to be encrypted or decrypted. The
third parameter, datalen, is the length in bytes of data, which must be a
multiple of 8. The fourth parameter, 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 parameter ivec is the 8-byte
initialization vector for the chaining. It is updated to the next ini‐
tialization vector upon return.
RETURN VALUES
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 parameter to routine.
Given a result status stat, the macro DES_FAILED(stat) is false only for
the first two statuses.
SEE ALSOcrypt(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
