// SPDX-License-Identifier: GPL-2.0+ | |
/* | |
* (C) Copyright 2015 Google, Inc | |
* | |
* (C) Copyright 2008-2014 Rockchip Electronics | |
* | |
* Rivest Cipher 4 (RC4) implementation | |
*/ | |
#include <rc4.h> | |
void rc4_encode(unsigned char *buf, unsigned int len, const 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]; | |
} | |
} |