blob: 720112d1fd8e90c312d721999b34697fbb68f1b1 [file] [log] [blame]
Tom Rini83d290c2018-05-06 17:58:06 -04001// SPDX-License-Identifier: GPL-2.0+
Simon Glass1acab962015-06-23 15:39:07 -06002/*
3 * (C) Copyright 2015 Google, Inc
4 *
5 * (C) Copyright 2008-2014 Rockchip Electronics
6 *
7 * Rivest Cipher 4 (RC4) implementation
Simon Glass1acab962015-06-23 15:39:07 -06008 */
9
10#ifndef USE_HOSTCC
11#include <common.h>
12#endif
13#include <rc4.h>
14
John Keeping93a6e602022-11-18 16:13:17 +000015void rc4_encode(unsigned char *buf, unsigned int len, const unsigned char key[16])
Simon Glass1acab962015-06-23 15:39:07 -060016{
17 unsigned char s[256], k[256], temp;
18 unsigned short i, j, t;
19 int ptr;
20
21 j = 0;
22 for (i = 0; i < 256; i++) {
23 s[i] = (unsigned char)i;
24 j &= 0x0f;
25 k[i] = key[j];
26 j++;
27 }
28
29 j = 0;
30 for (i = 0; i < 256; i++) {
31 j = (j + s[i] + k[i]) % 256;
32 temp = s[i];
33 s[i] = s[j];
34 s[j] = temp;
35 }
36
37 i = 0;
38 j = 0;
39 for (ptr = 0; ptr < len; ptr++) {
40 i = (i + 1) % 256;
41 j = (j + s[i]) % 256;
42 temp = s[i];
43 s[i] = s[j];
44 s[j] = temp;
45 t = (s[i] + (s[j] % 256)) % 256;
46 buf[ptr] = buf[ptr] ^ s[t];
47 }
48}