109 lines
2.8 KiB
C
109 lines
2.8 KiB
C
|
/*
|
||
|
|
* dlls/rsaenh/rc4.c
|
||
|
|
* RC4 functions
|
||
|
|
*
|
||
|
|
* Copyright 2004 Michael Jung
|
||
|
|
* Based on public domain code by Tom St Denis (tomstdenis@iahu.ca)
|
||
|
|
*
|
||
|
|
* This library is free software; you can redistribute it and/or
|
||
|
|
* modify it under the terms of the GNU Lesser General Public
|
||
|
|
* License as published by the Free Software Foundation; either
|
||
|
|
* version 2.1 of the License, or (at your option) any later version.
|
||
|
|
*
|
||
|
|
* This library is distributed in the hope that it will be useful,
|
||
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
||
|
|
* Lesser General Public License for more details.
|
||
|
|
*
|
||
|
|
* You should have received a copy of the GNU Lesser General Public
|
||
|
|
* License along with this library; if not, write to the Free Software
|
||
|
|
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
||
|
|
*/
|
||
|
|
|
||
|
|
/*
|
||
|
|
* This file contains code from the LibTomCrypt cryptographic
|
||
|
|
* library written by Tom St Denis (tomstdenis@iahu.ca). LibTomCrypt
|
||
|
|
* is in the public domain. The code in this file is tailored to
|
||
|
|
* special requirements. Take a look at http://libtomcrypt.org for the
|
||
|
|
* original version.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include "tomcrypt.h"
|
||
|
|
|
||
|
|
int rc4_start(prng_state *prng)
|
||
|
|
{
|
||
|
|
/* set keysize to zero */
|
||
|
|
prng->rc4.x = 0;
|
||
|
|
|
||
|
|
return CRYPT_OK;
|
||
|
|
}
|
||
|
|
|
||
|
|
int rc4_add_entropy(const unsigned char *buf, unsigned long len, prng_state *prng)
|
||
|
|
{
|
||
|
|
/* trim as required */
|
||
|
|
if (prng->rc4.x + len > 256) {
|
||
|
|
if (prng->rc4.x == 256) {
|
||
|
|
/* I can't possibly accept another byte, ok maybe a mint wafer... */
|
||
|
|
return CRYPT_OK;
|
||
|
|
} else {
|
||
|
|
/* only accept part of it */
|
||
|
|
len = 256 - prng->rc4.x;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
while (len--) {
|
||
|
|
prng->rc4.buf[prng->rc4.x++] = *buf++;
|
||
|
|
}
|
||
|
|
|
||
|
|
return CRYPT_OK;
|
||
|
|
}
|
||
|
|
|
||
|
|
int rc4_ready(prng_state *prng)
|
||
|
|
{
|
||
|
|
unsigned char key[256], tmp, *s;
|
||
|
|
int keylen, x, y, j;
|
||
|
|
|
||
|
|
/* extract the key */
|
||
|
|
s = prng->rc4.buf;
|
||
|
|
memcpy(key, s, 256);
|
||
|
|
keylen = prng->rc4.x;
|
||
|
|
|
||
|
|
/* make RC4 perm and shuffle */
|
||
|
|
for (x = 0; x < 256; x++) {
|
||
|
|
s[x] = x;
|
||
|
|
}
|
||
|
|
|
||
|
|
for (j = x = y = 0; x < 256; x++) {
|
||
|
|
y = (y + prng->rc4.buf[x] + key[j++]) & 255;
|
||
|
|
if (j == keylen) {
|
||
|
|
j = 0;
|
||
|
|
}
|
||
|
|
tmp = s[x]; s[x] = s[y]; s[y] = tmp;
|
||
|
|
}
|
||
|
|
prng->rc4.x = 0;
|
||
|
|
prng->rc4.y = 0;
|
||
|
|
|
||
|
|
return CRYPT_OK;
|
||
|
|
}
|
||
|
|
|
||
|
|
unsigned long rc4_read(unsigned char *buf, unsigned long len, prng_state *prng)
|
||
|
|
{
|
||
|
|
unsigned char x, y, *s, tmp;
|
||
|
|
unsigned long n;
|
||
|
|
|
||
|
|
n = len;
|
||
|
|
x = prng->rc4.x;
|
||
|
|
y = prng->rc4.y;
|
||
|
|
s = prng->rc4.buf;
|
||
|
|
while (len--) {
|
||
|
|
x = (x + 1) & 255;
|
||
|
|
y = (y + s[x]) & 255;
|
||
|
|
tmp = s[x]; s[x] = s[y]; s[y] = tmp;
|
||
|
|
tmp = (s[x] + s[y]) & 255;
|
||
|
|
*buf++ ^= s[tmp];
|
||
|
|
}
|
||
|
|
prng->rc4.x = x;
|
||
|
|
prng->rc4.y = y;
|
||
|
|
return n;
|
||
|
|
}
|