rc4.c
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/*
* (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];
}
}