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 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 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 parameter to routine.
Given a result status stat,
the macro DES_FAILED(stat) is false only for the
first two statuses.
VERSIONS
These routines are present in libc 4.6.27 and later, and
in glibc 2.1 and later.
CONFORMING TO
4.3BSD. Not in POSIX.1-2001.
SEE ALSO
des(1), crypt(3) and xcrypt(3)
@(#)des_crypt.3
2.1 88/08/11 4.0 RPCSRC; from 1.16 88/03/02 SMI;
Taken from libc4 sources, which say:
Copyright (C) 1993 Eric Young - can be distributed under GPL.
However, the above header line suggests that this file in fact is
Copyright Sun Microsystems, Inc (and is provided for unrestricted use,
see other Sun RPC sources).
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