[457] | 1 | /*
|
---|
| 2 | * An implementation of the ARCFOUR algorithm
|
---|
| 3 | *
|
---|
| 4 | * Based on XySSL: Copyright (C) 2006-2008 Christophe Devine
|
---|
| 5 | *
|
---|
| 6 | * Copyright (C) 2009 Paul Bakker <polarssl_maintainer at polarssl dot org>
|
---|
| 7 | *
|
---|
| 8 | * All rights reserved.
|
---|
| 9 | *
|
---|
| 10 | * Redistribution and use in source and binary forms, with or without
|
---|
| 11 | * modification, are permitted provided that the following conditions
|
---|
| 12 | * are met:
|
---|
| 13 | *
|
---|
| 14 | * * Redistributions of source code must retain the above copyright
|
---|
| 15 | * notice, this list of conditions and the following disclaimer.
|
---|
| 16 | * * Redistributions in binary form must reproduce the above copyright
|
---|
| 17 | * notice, this list of conditions and the following disclaimer in the
|
---|
| 18 | * documentation and/or other materials provided with the distribution.
|
---|
| 19 | * * Neither the names of PolarSSL or XySSL nor the names of its contributors
|
---|
| 20 | * may be used to endorse or promote products derived from this software
|
---|
| 21 | * without specific prior written permission.
|
---|
| 22 | *
|
---|
| 23 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
---|
| 24 | * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
---|
| 25 | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
|
---|
| 26 | * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
|
---|
| 27 | * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
|
---|
| 28 | * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
|
---|
| 29 | * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
|
---|
| 30 | * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
|
---|
| 31 | * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
|
---|
| 32 | * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
|
---|
| 33 | * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
---|
| 34 | */
|
---|
| 35 | /*
|
---|
| 36 | * The ARCFOUR algorithm was publicly disclosed on 94/09.
|
---|
| 37 | *
|
---|
| 38 | * http://groups.google.com/group/sci.crypt/msg/10a300c9d21afca0
|
---|
| 39 | */
|
---|
| 40 |
|
---|
| 41 | #include "netif/ppp/ppp_opts.h"
|
---|
| 42 | #if PPP_SUPPORT && LWIP_INCLUDED_POLARSSL_ARC4
|
---|
| 43 |
|
---|
| 44 | #include "netif/ppp/polarssl/arc4.h"
|
---|
| 45 | /*
|
---|
| 46 | * ARC4 key schedule
|
---|
| 47 | */
|
---|
| 48 | void arc4_setup( arc4_context *ctx, unsigned char *key, int keylen )
|
---|
| 49 | {
|
---|
| 50 | int i, j, k, a;
|
---|
| 51 | unsigned char *m;
|
---|
| 52 |
|
---|
| 53 | ctx->x = 0;
|
---|
| 54 | ctx->y = 0;
|
---|
| 55 | m = ctx->m;
|
---|
| 56 |
|
---|
| 57 | for( i = 0; i < 256; i++ )
|
---|
| 58 | m[i] = (unsigned char) i;
|
---|
| 59 |
|
---|
| 60 | j = k = 0;
|
---|
| 61 |
|
---|
| 62 | for( i = 0; i < 256; i++, k++ )
|
---|
| 63 | {
|
---|
| 64 | if( k >= keylen ) k = 0;
|
---|
| 65 |
|
---|
| 66 | a = m[i];
|
---|
| 67 | j = ( j + a + key[k] ) & 0xFF;
|
---|
| 68 | m[i] = m[j];
|
---|
| 69 | m[j] = (unsigned char) a;
|
---|
| 70 | }
|
---|
| 71 | }
|
---|
| 72 |
|
---|
| 73 | /*
|
---|
| 74 | * ARC4 cipher function
|
---|
| 75 | */
|
---|
| 76 | void arc4_crypt( arc4_context *ctx, unsigned char *buf, int buflen )
|
---|
| 77 | {
|
---|
| 78 | int i, x, y, a, b;
|
---|
| 79 | unsigned char *m;
|
---|
| 80 |
|
---|
| 81 | x = ctx->x;
|
---|
| 82 | y = ctx->y;
|
---|
| 83 | m = ctx->m;
|
---|
| 84 |
|
---|
| 85 | for( i = 0; i < buflen; i++ )
|
---|
| 86 | {
|
---|
| 87 | x = ( x + 1 ) & 0xFF; a = m[x];
|
---|
| 88 | y = ( y + a ) & 0xFF; b = m[y];
|
---|
| 89 |
|
---|
| 90 | m[x] = (unsigned char) b;
|
---|
| 91 | m[y] = (unsigned char) a;
|
---|
| 92 |
|
---|
| 93 | buf[i] = (unsigned char)
|
---|
| 94 | ( buf[i] ^ m[(unsigned char)( a + b )] );
|
---|
| 95 | }
|
---|
| 96 |
|
---|
| 97 | ctx->x = x;
|
---|
| 98 | ctx->y = y;
|
---|
| 99 | }
|
---|
| 100 |
|
---|
| 101 | #endif /* PPP_SUPPORT && LWIP_INCLUDED_POLARSSL_DES */
|
---|