[apple/xnu.git] / bsd / crypto / rc4 / rc4.c

/*
 * rc4.c
 *
 * Copyright (c) 1996-2000 Whistle Communications, Inc.
 * All rights reserved.
 *
 * Subject to the following obligations and disclaimer of warranty, use and
 * redistribution of this software, in source or object code forms, with or
 * without modifications are expressly permitted by Whistle Communications;
 * provided, however, that:
 * 1. Any and all reproductions of the source or object code must include the
 *    copyright notice above and the following disclaimer of warranties; and
 * 2. No rights are granted, in any manner or form, to use Whistle
 *    Communications, Inc. trademarks, including the mark "WHISTLE
 *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
 *    such appears in the above copyright notice or in the software.
 *
 * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
 * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
 * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
 * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
 * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
 * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
 * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
 * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
 * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
 * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
 * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER 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 WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 *
 * $FreeBSD: src/sys/crypto/rc4/rc4.c,v 1.2.2.1 2000/04/18 04:48:31 archie Exp $
 */

#include <sys/types.h>
#include <crypto/rc4/rc4.h>

static __inline void
swap_bytes(u_char *a, u_char *b)
{
	u_char temp;

	temp = *a;
	*a = *b;
	*b = temp;
}

/*
 * Initialize an RC4 state buffer using the supplied key,
 * which can have arbitrary length.
 */
void
rc4_init(struct rc4_state *const state, const u_char *key, int keylen)
{
	u_char j;
	int i;

	/* Initialize state with identity permutation */
	for (i = 0; i < 256; i++) {
		state->perm[i] = (u_char)i;
	}
	state->index1 = 0;
	state->index2 = 0;

	/* Randomize the permutation using key data */
	for (j = i = 0; i < 256; i++) {
		j += state->perm[i] + key[i % keylen];
		swap_bytes(&state->perm[i], &state->perm[j]);
	}
}

/*
 * Encrypt some data using the supplied RC4 state buffer.
 * The input and output buffers may be the same buffer.
 * Since RC4 is a stream cypher, this function is used
 * for both encryption and decryption.
 */
void
rc4_crypt(struct rc4_state *const state,
    const u_char *inbuf, u_char *outbuf, int buflen)
{
	int i;
	u_char j;

	for (i = 0; i < buflen; i++) {
		/* Update modification indicies */
		state->index1++;
		state->index2 += state->perm[state->index1];

		/* Modify permutation */
		swap_bytes(&state->perm[state->index1],
		    &state->perm[state->index2]);

		/* Encrypt/decrypt next byte */
		j = state->perm[state->index1] + state->perm[state->index2];
		outbuf[i] = inbuf[i] ^ state->perm[j];
	}
}
Commit	Line	Data
9bccf70c A	1	/*
	2	* rc4.c
	3	*
	4	* Copyright (c) 1996-2000 Whistle Communications, Inc.
	5	* All rights reserved.
0a7de745	6	*
9bccf70c A	7	* Subject to the following obligations and disclaimer of warranty, use and
	8	* redistribution of this software, in source or object code forms, with or
	9	* without modifications are expressly permitted by Whistle Communications;
	10	* provided, however, that:
	11	* 1. Any and all reproductions of the source or object code must include the
	12	* copyright notice above and the following disclaimer of warranties; and
	13	* 2. No rights are granted, in any manner or form, to use Whistle
	14	* Communications, Inc. trademarks, including the mark "WHISTLE
	15	* COMMUNICATIONS" on advertising, endorsements, or otherwise except as
	16	* such appears in the above copyright notice or in the software.
0a7de745	17	*
9bccf70c A	18	* THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
	19	* TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
	20	* REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
	21	* INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
	22	* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
	23	* WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
	24	* REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
	25	* SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
	26	* IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
	27	* RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
	28	* WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
	29	* PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
	30	* SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
	31	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	32	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	33	* THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
	34	* OF SUCH DAMAGE.
	35	*
	36	* $FreeBSD: src/sys/crypto/rc4/rc4.c,v 1.2.2.1 2000/04/18 04:48:31 archie Exp $
	37	*/
	38
	39	#include <sys/types.h>
	40	#include <crypto/rc4/rc4.h>
	41
	42	static __inline void
	43	swap_bytes(u_char a, u_char b)
	44	{
	45	u_char temp;
	46
	47	temp = *a;
	48	a = b;
	49	*b = temp;
	50	}
	51
	52	/*
	53	* Initialize an RC4 state buffer using the supplied key,
	54	* which can have arbitrary length.
	55	*/
	56	void
	57	rc4_init(struct rc4_state const state, const u_char key, int keylen)
	58	{
	59	u_char j;
	60	int i;
	61
	62	/* Initialize state with identity permutation */
0a7de745 A	63	for (i = 0; i < 256; i++) {
	64	state->perm[i] = (u_char)i;
	65	}
9bccf70c A	66	state->index1 = 0;
9bccf70c A	67	state->index2 = 0;
0a7de745	68
9bccf70c A	69	/* Randomize the permutation using key data */
9bccf70c A	70	for (j = i = 0; i < 256; i++) {
0a7de745	71	j += state->perm[i] + key[i % keylen];
9bccf70c A	72	swap_bytes(&state->perm[i], &state->perm[j]);
	73	}
	74	}
	75
	76	/*
	77	* Encrypt some data using the supplied RC4 state buffer.
	78	* The input and output buffers may be the same buffer.
	79	* Since RC4 is a stream cypher, this function is used
	80	* for both encryption and decryption.
	81	*/
	82	void
	83	rc4_crypt(struct rc4_state *const state,
0a7de745	84	const u_char inbuf, u_char outbuf, int buflen)
9bccf70c A	85	{
	86	int i;
	87	u_char j;
	88
	89	for (i = 0; i < buflen; i++) {
9bccf70c A	90	/* Update modification indicies */
	91	state->index1++;
	92	state->index2 += state->perm[state->index1];
	93
	94	/* Modify permutation */
	95	swap_bytes(&state->perm[state->index1],
	96	&state->perm[state->index2]);
	97
	98	/* Encrypt/decrypt next byte */
	99	j = state->perm[state->index1] + state->perm[state->index2];
	100	outbuf[i] = inbuf[i] ^ state->perm[j];
	101	}
	102	}