/* $OpenBSD: rc4.c,v 1.15 2025/08/17 08:04:25 jsing Exp $ */ /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) * All rights reserved. * * This package is an SSL implementation written * by Eric Young (eay@cryptsoft.com). * The implementation was written so as to conform with Netscapes SSL. * * This library is free for commercial and non-commercial use as long as * the following conditions are aheared to. The following conditions * apply to all code found in this distribution, be it the RC4, RSA, * lhash, DES, etc., code; not just the SSL code. The SSL documentation * included with this distribution is covered by the same copyright terms * except that the holder is Tim Hudson (tjh@cryptsoft.com). * * Copyright remains Eric Young's, and as such any Copyright notices in * the code are not to be removed. * If this package is used in a product, Eric Young should be given attribution * as the author of the parts of the library used. * This can be in the form of a textual message at program startup or * in documentation (online or textual) provided with the package. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the copyright * notice, this list of conditions and the following disclaimer. * 2. 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. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * "This product includes cryptographic software written by * Eric Young (eay@cryptsoft.com)" * The word 'cryptographic' can be left out if the rouines from the library * being used are not cryptographic related :-). * 4. If you include any Windows specific code (or a derivative thereof) from * the apps directory (application code) you must include an acknowledgement: * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" * * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``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 AUTHOR 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 licence and distribution terms for any publically available version or * derivative of this code cannot be changed. i.e. this code cannot simply be * copied and put under another distribution licence * [including the GNU Public Licence.] */ #include <endian.h> #include <stdint.h> #include <openssl/rc4.h> #include "crypto_arch.h" #ifdef HAVE_RC4_INTERNAL void rc4_internal(RC4_KEY *key, size_t len, const uint8_t *in, uint8_t *out); #else static inline RC4_INT rc4_step(RC4_INT *d, RC4_INT *x, RC4_INT *y) { RC4_INT tx, ty; *x = (*x + 1) & 0xff; tx = d[*x]; *y = (tx + *y) & 0xff; d[*x] = ty = d[*y]; d[*y] = tx; return d[(tx + ty) & 0xff]; } #if BYTE_ORDER == BIG_ENDIAN static inline uint64_t rc4_chunk(RC4_INT *d, RC4_INT *x, RC4_INT *y) { uint64_t chunk = 0; size_t i; for (i = 0; i < 8; i++) chunk = chunk << 8 | (uint64_t)rc4_step(d, x, y); return chunk; } #else static inline uint64_t rc4_chunk(RC4_INT *d, RC4_INT *x, RC4_INT *y) { uint64_t chunk = 0; size_t i; for (i = 0; i < 8; i++) chunk |= (uint64_t)rc4_step(d, x, y) << (i * 8); return chunk; } #endif static void rc4_internal(RC4_KEY *key, size_t len, const uint8_t *in, uint8_t *out) { RC4_INT *d, x, y; size_t i; x = key->x; y = key->y; d = key->data; /* Process uint64_t chunks if 8 byte aligned. */ if ((((size_t)in | (size_t)out) % 8) == 0) { while (len >= 8) { *(uint64_t *)out = *(const uint64_t *)in ^ rc4_chunk(d, &x, &y); in += 8; out += 8; len -= 8; } } while (len >= 8) { for (i = 0; i < 8; i++) out[i] = rc4_step(d, &x, &y) ^ in[i]; in += 8; out += 8; len -= 8; } for (i = 0; i < len; i++) out[i] = rc4_step(d, &x, &y) ^ in[i]; key->x = x; key->y = y; } #endif #ifdef HAVE_RC4_SET_KEY_INTERNAL void rc4_set_key_internal(RC4_KEY *key, int len, const uint8_t *data); #else static inline void rc4_set_key_internal(RC4_KEY *key, int len, const uint8_t *data) { RC4_INT *d, tmp; int idx1, idx2; int i, j; d = key->data; key->x = 0; key->y = 0; idx1 = idx2 = 0; for (i = 0; i < 256; i++) d[i] = i; for (i = 0; i < 256; i += 4) { for (j = 0; j < 4; j++) { tmp = d[i + j]; idx2 = (data[idx1] + tmp + idx2) & 0xff; d[i + j] = d[idx2]; d[idx2] = tmp; if (++idx1 == len) idx1 = 0; } } } #endif void RC4(RC4_KEY *key, size_t len, const unsigned char *indata, unsigned char *outdata) { rc4_internal(key, len, indata, outdata); } LCRYPTO_ALIAS(RC4); void RC4_set_key(RC4_KEY *key, int len, const unsigned char *data) { rc4_set_key_internal(key, len, data); } LCRYPTO_ALIAS(RC4_set_key);
