| /* |
| * An implementation of the ARCFOUR algorithm |
| * |
| * Based on XySSL: Copyright (C) 2006-2008 Christophe Devine |
| * |
| * Copyright (C) 2009 Paul Bakker <polarssl_maintainer at polarssl dot org> |
| * |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * * Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * * Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * * Neither the names of PolarSSL or XySSL nor the names of its contributors |
| * may be used to endorse or promote products derived from this software |
| * without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
| * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED |
| * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
| * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
| * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
| * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
| * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| /* |
| * The ARCFOUR algorithm was publicly disclosed on 94/09. |
| * |
| * http://groups.google.com/group/sci.crypt/msg/10a300c9d21afca0 |
| */ |
| |
| #include "netif/ppp/ppp_opts.h" |
| #if PPP_SUPPORT && LWIP_INCLUDED_POLARSSL_ARC4 |
| |
| #include "netif/ppp/polarssl/arc4.h" |
| /* |
| * ARC4 key schedule |
| */ |
| void arc4_setup( arc4_context *ctx, unsigned char *key, int keylen ) |
| { |
| int i, j, k, a; |
| unsigned char *m; |
| |
| ctx->x = 0; |
| ctx->y = 0; |
| m = ctx->m; |
| |
| for( i = 0; i < 256; i++ ) |
| m[i] = (unsigned char) i; |
| |
| j = k = 0; |
| |
| for( i = 0; i < 256; i++, k++ ) |
| { |
| if( k >= keylen ) k = 0; |
| |
| a = m[i]; |
| j = ( j + a + key[k] ) & 0xFF; |
| m[i] = m[j]; |
| m[j] = (unsigned char) a; |
| } |
| } |
| |
| /* |
| * ARC4 cipher function |
| */ |
| void arc4_crypt( arc4_context *ctx, unsigned char *buf, int buflen ) |
| { |
| int i, x, y, a, b; |
| unsigned char *m; |
| |
| x = ctx->x; |
| y = ctx->y; |
| m = ctx->m; |
| |
| for( i = 0; i < buflen; i++ ) |
| { |
| x = ( x + 1 ) & 0xFF; a = m[x]; |
| y = ( y + a ) & 0xFF; b = m[y]; |
| |
| m[x] = (unsigned char) b; |
| m[y] = (unsigned char) a; |
| |
| buf[i] = (unsigned char) |
| ( buf[i] ^ m[(unsigned char)( a + b )] ); |
| } |
| |
| ctx->x = x; |
| ctx->y = y; |
| } |
| |
| #endif /* PPP_SUPPORT && LWIP_INCLUDED_POLARSSL_DES */ |