12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364656667686970717273747576 |
- /* arc4.c
- *
- * Copyright (C) 2006-2011 Sawtooth Consulting Ltd.
- *
- * This file is part of CyaSSL.
- *
- * CyaSSL is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * CyaSSL 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 General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
- */
- #include "arc4.h"
- void Arc4SetKey(Arc4* arc4, const byte* key, word32 length)
- {
- word32 i;
- word32 keyIndex = 0, stateIndex = 0;
- arc4->x = 1;
- arc4->y = 0;
- for (i = 0; i < ARC4_STATE_SIZE; i++)
- arc4->state[i] = i;
- for (i = 0; i < ARC4_STATE_SIZE; i++) {
- word32 a = arc4->state[i];
- stateIndex += key[keyIndex] + a;
- stateIndex &= 0xFF;
- arc4->state[i] = arc4->state[stateIndex];
- arc4->state[stateIndex] = a;
- if (++keyIndex >= length)
- keyIndex = 0;
- }
- }
- static INLINE word32 MakeByte(word32* x, word32* y, byte* s)
- {
- word32 a = s[*x], b;
- *y = (*y+a) & 0xff;
- b = s[*y];
- s[*x] = b;
- s[*y] = a;
- *x = (*x+1) & 0xff;
- return s[(a+b) & 0xff];
- }
- void Arc4Process(Arc4* arc4, byte* out, const byte* in, word32 length)
- {
- word32 x = arc4->x;
- word32 y = arc4->y;
- while(length--)
- *out++ = *in++ ^ MakeByte(&x, &y, arc4->state);
- arc4->x = x;
- arc4->y = y;
- }
|