3 * The arcfour/rc4 stream cipher.
6 /* nettle, low-level cryptographics library
8 * Copyright (C) 2001, 2004 Niels Möller
10 * The nettle library is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU Lesser General Public License as published by
12 * the Free Software Foundation; either version 2.1 of the License, or (at your
13 * option) any later version.
15 * The nettle library is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
17 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
18 * License for more details.
20 * You should have received a copy of the GNU Lesser General Public License
21 * along with the nettle library; see the file COPYING.LIB. If not, write to
22 * the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
35 arcfour_crypt(struct arcfour_ctx *ctx,
36 unsigned length, uint8_t *dst,
39 register uint8_t i, j;
42 i = ctx->i; j = ctx->j;
48 sj = ctx->S[i] = ctx->S[j];
50 *dst++ = *src++ ^ ctx->S[ (si + sj) & 0xff ];
52 ctx->i = i; ctx->j = j;