[people/ms/u-boot.git] / lib / rc4.c

/*
 * (C) Copyright 2015 Google, Inc
 *
 * (C) Copyright 2008-2014 Rockchip Electronics
 *
 * Rivest Cipher 4 (RC4) implementation
 *
 * SPDX-License-Identifier:	GPL-2.0+
 */

#ifndef USE_HOSTCC
#include <common.h>
#endif
#include <rc4.h>

void rc4_encode(unsigned char *buf, unsigned int len, unsigned char key[16])
{
	unsigned char s[256], k[256], temp;
	unsigned short i, j, t;
	int ptr;

	j = 0;
	for (i = 0; i < 256; i++) {
		s[i] = (unsigned char)i;
		j &= 0x0f;
		k[i] = key[j];
		j++;
	}

	j = 0;
	for (i = 0; i < 256; i++) {
		j = (j + s[i] + k[i]) % 256;
		temp = s[i];
		s[i] = s[j];
		s[j] = temp;
	}

	i = 0;
	j = 0;
	for (ptr = 0; ptr < len; ptr++) {
		i = (i + 1) % 256;
		j = (j + s[i]) % 256;
		temp = s[i];
		s[i] = s[j];
		s[j] = temp;
		t = (s[i] + (s[j] % 256)) % 256;
		buf[ptr] = buf[ptr] ^ s[t];
	}
}
Commit	Line	Data
1acab96d SG	1	/*
	2	* (C) Copyright 2015 Google, Inc
	3	*
	4	* (C) Copyright 2008-2014 Rockchip Electronics
	5	*
	6	* Rivest Cipher 4 (RC4) implementation
	7	*
	8	* SPDX-License-Identifier: GPL-2.0+
	9	*/
	10
	11	#ifndef USE_HOSTCC
	12	#include <common.h>
	13	#endif
	14	#include <rc4.h>
	15
	16	void rc4_encode(unsigned char *buf, unsigned int len, unsigned char key[16])
	17	{
	18	unsigned char s[256], k[256], temp;
	19	unsigned short i, j, t;
	20	int ptr;
	21
	22	j = 0;
	23	for (i = 0; i < 256; i++) {
	24	s[i] = (unsigned char)i;
	25	j &= 0x0f;
	26	k[i] = key[j];
	27	j++;
	28	}
	29
	30	j = 0;
	31	for (i = 0; i < 256; i++) {
	32	j = (j + s[i] + k[i]) % 256;
	33	temp = s[i];
	34	s[i] = s[j];
	35	s[j] = temp;
	36	}
	37
	38	i = 0;
	39	j = 0;
	40	for (ptr = 0; ptr < len; ptr++) {
	41	i = (i + 1) % 256;
	42	j = (j + s[i]) % 256;
	43	temp = s[i];
	44	s[i] = s[j];
	45	s[j] = temp;
	46	t = (s[i] + (s[j] % 256)) % 256;
	47	buf[ptr] = buf[ptr] ^ s[t];
	48	}
	49	}