blob: 89d15f3c821be7ba7f79e82c6630a3f16951b825 [file] [log] [blame]
Simon Glass1acab962015-06-23 15:39:07 -06001/*
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
16void 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}