1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * (C) Copyright 2015 Google, Inc 4 * 5 * (C) Copyright 2008-2014 Rockchip Electronics 6 * 7 * Rivest Cipher 4 (RC4) implementation 8 */ 9 10 #ifndef USE_HOSTCC 11 #include <common.h> 12 #endif 13 #include <rc4.h> 14 15 void rc4_encode(unsigned char *buf, unsigned int len, unsigned char key[16]) 16 { 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 } 49