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/* 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 <openssl/rc4.h>
#if defined(OPENSSL_NO_ASM) || \
(!defined(OPENSSL_X86_64) && !defined(OPENSSL_X86))
#if defined(OPENSSL_64_BIT)
#define RC4_CHUNK uint64_t
#elif defined(OPENSSL_32_BIT)
#define RC4_CHUNK uint32_t
#else
#error "Unknown word size"
#endif
/* RC4 as implemented from a posting from
* Newsgroups: sci.crypt
* From: sterndark@netcom.com (David Sterndark)
* Subject: RC4 Algorithm revealed.
* Message-ID: <sternCvKL4B.Hyy@netcom.com>
* Date: Wed, 14 Sep 1994 06:35:31 GMT */
void RC4(RC4_KEY *key, size_t len, const uint8_t *in, uint8_t *out) {
uint32_t *d;
uint32_t x, y, tx, ty;
size_t i;
x = key->x;
y = key->y;
d = key->data;
#define RC4_STEP \
(x = (x + 1) & 0xff, tx = d[x], y = (tx + y) & 0xff, ty = d[y], d[y] = tx, \
d[x] = ty, (RC4_CHUNK)d[(tx + ty) & 0xff])
if ((((size_t)in & (sizeof(RC4_CHUNK) - 1)) |
((size_t)out & (sizeof(RC4_CHUNK) - 1))) == 0) {
RC4_CHUNK ichunk, otp;
const union {
long one;
char little;
} is_endian = {1};
/* I reckon we can afford to implement both endian
* cases and to decide which way to take at run-time
* because the machine code appears to be very compact
* and redundant 1-2KB is perfectly tolerable (i.e.
* in case the compiler fails to eliminate it:-). By
* suggestion from Terrel Larson <terr@terralogic.net>
* who also stands for the is_endian union:-)
*
* Special notes.
*
* - is_endian is declared automatic as doing otherwise
* (declaring static) prevents gcc from eliminating
* the redundant code;
* - compilers (those I've tried) don't seem to have
* problems eliminating either the operators guarded
* by "if (sizeof(RC4_CHUNK)==8)" or the condition
* expressions themselves so I've got 'em to replace
* corresponding #ifdefs from the previous version;
* - I chose to let the redundant switch cases when
* sizeof(RC4_CHUNK)!=8 be (were also #ifdefed
* before);
* - in case you wonder "&(sizeof(RC4_CHUNK)*8-1)" in
* [LB]ESHFT guards against "shift is out of range"
* warnings when sizeof(RC4_CHUNK)!=8
*
* <appro@fy.chalmers.se> */
if (!is_endian.little) { /* BIG-ENDIAN CASE */
#define BESHFT(c) \
(((sizeof(RC4_CHUNK) - (c) - 1) * 8) & (sizeof(RC4_CHUNK) * 8 - 1))
for (; len & (0 - sizeof(RC4_CHUNK)); len -= sizeof(RC4_CHUNK)) {
ichunk = *(RC4_CHUNK *)in;
otp = RC4_STEP << BESHFT(0);
otp |= RC4_STEP << BESHFT(1);
otp |= RC4_STEP << BESHFT(2);
otp |= RC4_STEP << BESHFT(3);
#if defined(OPENSSL_64_BIT)
otp |= RC4_STEP << BESHFT(4);
otp |= RC4_STEP << BESHFT(5);
otp |= RC4_STEP << BESHFT(6);
otp |= RC4_STEP << BESHFT(7);
#endif
*(RC4_CHUNK *)out = otp ^ ichunk;
in += sizeof(RC4_CHUNK);
out += sizeof(RC4_CHUNK);
}
} else { /* LITTLE-ENDIAN CASE */
#define LESHFT(c) (((c) * 8) & (sizeof(RC4_CHUNK) * 8 - 1))
for (; len & (0 - sizeof(RC4_CHUNK)); len -= sizeof(RC4_CHUNK)) {
ichunk = *(RC4_CHUNK *)in;
otp = RC4_STEP;
otp |= RC4_STEP << 8;
otp |= RC4_STEP << 16;
otp |= RC4_STEP << 24;
#if defined(OPENSSL_64_BIT)
otp |= RC4_STEP << LESHFT(4);
otp |= RC4_STEP << LESHFT(5);
otp |= RC4_STEP << LESHFT(6);
otp |= RC4_STEP << LESHFT(7);
#endif
*(RC4_CHUNK *)out = otp ^ ichunk;
in += sizeof(RC4_CHUNK);
out += sizeof(RC4_CHUNK);
}
}
}
#define LOOP(in, out) \
x = ((x + 1) & 0xff); \
tx = d[x]; \
y = (tx + y) & 0xff; \
d[x] = ty = d[y]; \
d[y] = tx; \
(out) = d[(tx + ty) & 0xff] ^ (in);
#ifndef RC4_INDEX
#define RC4_LOOP(a, b, i) LOOP(*((a)++), *((b)++))
#else
#define RC4_LOOP(a, b, i) LOOP(a[i], b[i])
#endif
i = len >> 3;
if (i) {
for (;;) {
RC4_LOOP(in, out, 0);
RC4_LOOP(in, out, 1);
RC4_LOOP(in, out, 2);
RC4_LOOP(in, out, 3);
RC4_LOOP(in, out, 4);
RC4_LOOP(in, out, 5);
RC4_LOOP(in, out, 6);
RC4_LOOP(in, out, 7);
#ifdef RC4_INDEX
in += 8;
out += 8;
#endif
if (--i == 0) {
break;
}
}
}
i = len & 0x07;
if (i) {
for (;;) {
RC4_LOOP(in, out, 0);
if (--i == 0) {
break;
}
RC4_LOOP(in, out, 1);
if (--i == 0) {
break;
}
RC4_LOOP(in, out, 2);
if (--i == 0) {
break;
}
RC4_LOOP(in, out, 3);
if (--i == 0) {
break;
}
RC4_LOOP(in, out, 4);
if (--i == 0) {
break;
}
RC4_LOOP(in, out, 5);
if (--i == 0) {
break;
}
RC4_LOOP(in, out, 6);
if (--i == 0) {
break;
}
}
}
key->x = x;
key->y = y;
}
void RC4_set_key(RC4_KEY *rc4key, unsigned len, const uint8_t *key) {
uint32_t tmp;
int id1, id2;
uint32_t *d;
unsigned int i;
d = &rc4key->data[0];
rc4key->x = 0;
rc4key->y = 0;
id1 = id2 = 0;
#define SK_LOOP(d, n) \
{ \
tmp = d[(n)]; \
id2 = (key[id1] + tmp + id2) & 0xff; \
if (++id1 == len) \
id1 = 0; \
d[(n)] = d[id2]; \
d[id2] = tmp; \
}
for (i = 0; i < 256; i++) {
d[i] = i;
}
for (i = 0; i < 256; i += 4) {
SK_LOOP(d, i + 0);
SK_LOOP(d, i + 1);
SK_LOOP(d, i + 2);
SK_LOOP(d, i + 3);
}
}
#else
/* In this case several functions are provided by asm code. However, one cannot
* control asm symbol visibility with command line flags and such so they are
* always hidden and wrapped by these C functions, which can be so
* controlled. */
void asm_RC4(RC4_KEY *key, size_t len, const uint8_t *in, uint8_t *out);
void RC4(RC4_KEY *key, size_t len, const uint8_t *in, uint8_t *out) {
asm_RC4(key, len, in, out);
}
void asm_RC4_set_key(RC4_KEY *rc4key, unsigned len, const uint8_t *key);
void RC4_set_key(RC4_KEY *rc4key, unsigned len, const uint8_t *key) {
asm_RC4_set_key(rc4key, len, key);
}
#endif /* OPENSSL_NO_ASM || (!OPENSSL_X86_64 && !OPENSSL_X86) */