1/* 2 * Copyright (c) 2004 Kungliga Tekniska H��gskolan 3 * (Royal Institute of Technology, Stockholm, Sweden). 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * 3. Neither the name of the Institute nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34#include <config.h> 35 36#include "rc2.h" 37#include <stdio.h> 38#include <stdlib.h> 39#include <string.h> 40 41/* 42 * Implemented from Peter Gutmann's "Specification for Ron Rivests Cipher No.2" 43 * rfc2268 and "On the Design and Security of RC2" was also useful. 44 */ 45 46static unsigned int Sbox[256] = { 47 0xd9, 0x78, 0xf9, 0xc4, 0x19, 0xdd, 0xb5, 0xed, 48 0x28, 0xe9, 0xfd, 0x79, 0x4a, 0xa0, 0xd8, 0x9d, 49 0xc6, 0x7e, 0x37, 0x83, 0x2b, 0x76, 0x53, 0x8e, 50 0x62, 0x4c, 0x64, 0x88, 0x44, 0x8b, 0xfb, 0xa2, 51 0x17, 0x9a, 0x59, 0xf5, 0x87, 0xb3, 0x4f, 0x13, 52 0x61, 0x45, 0x6d, 0x8d, 0x09, 0x81, 0x7d, 0x32, 53 0xbd, 0x8f, 0x40, 0xeb, 0x86, 0xb7, 0x7b, 0x0b, 54 0xf0, 0x95, 0x21, 0x22, 0x5c, 0x6b, 0x4e, 0x82, 55 0x54, 0xd6, 0x65, 0x93, 0xce, 0x60, 0xb2, 0x1c, 56 0x73, 0x56, 0xc0, 0x14, 0xa7, 0x8c, 0xf1, 0xdc, 57 0x12, 0x75, 0xca, 0x1f, 0x3b, 0xbe, 0xe4, 0xd1, 58 0x42, 0x3d, 0xd4, 0x30, 0xa3, 0x3c, 0xb6, 0x26, 59 0x6f, 0xbf, 0x0e, 0xda, 0x46, 0x69, 0x07, 0x57, 60 0x27, 0xf2, 0x1d, 0x9b, 0xbc, 0x94, 0x43, 0x03, 61 0xf8, 0x11, 0xc7, 0xf6, 0x90, 0xef, 0x3e, 0xe7, 62 0x06, 0xc3, 0xd5, 0x2f, 0xc8, 0x66, 0x1e, 0xd7, 63 0x08, 0xe8, 0xea, 0xde, 0x80, 0x52, 0xee, 0xf7, 64 0x84, 0xaa, 0x72, 0xac, 0x35, 0x4d, 0x6a, 0x2a, 65 0x96, 0x1a, 0xd2, 0x71, 0x5a, 0x15, 0x49, 0x74, 66 0x4b, 0x9f, 0xd0, 0x5e, 0x04, 0x18, 0xa4, 0xec, 67 0xc2, 0xe0, 0x41, 0x6e, 0x0f, 0x51, 0xcb, 0xcc, 68 0x24, 0x91, 0xaf, 0x50, 0xa1, 0xf4, 0x70, 0x39, 69 0x99, 0x7c, 0x3a, 0x85, 0x23, 0xb8, 0xb4, 0x7a, 70 0xfc, 0x02, 0x36, 0x5b, 0x25, 0x55, 0x97, 0x31, 71 0x2d, 0x5d, 0xfa, 0x98, 0xe3, 0x8a, 0x92, 0xae, 72 0x05, 0xdf, 0x29, 0x10, 0x67, 0x6c, 0xba, 0xc9, 73 0xd3, 0x00, 0xe6, 0xcf, 0xe1, 0x9e, 0xa8, 0x2c, 74 0x63, 0x16, 0x01, 0x3f, 0x58, 0xe2, 0x89, 0xa9, 75 0x0d, 0x38, 0x34, 0x1b, 0xab, 0x33, 0xff, 0xb0, 76 0xbb, 0x48, 0x0c, 0x5f, 0xb9, 0xb1, 0xcd, 0x2e, 77 0xc5, 0xf3, 0xdb, 0x47, 0xe5, 0xa5, 0x9c, 0x77, 78 0x0a, 0xa6, 0x20, 0x68, 0xfe, 0x7f, 0xc1, 0xad 79}; 80 81void 82RC2_set_key(RC2_KEY *key, int len, const unsigned char *data, int bits) 83{ 84 unsigned char k[128]; 85 int j, T8, TM; 86 87 if (len <= 0) 88 abort(); 89 if (len > 128) 90 len = 128; 91 if (bits <= 0 || bits > 1024) 92 bits = 1024; 93 94 for (j = 0; j < len; j++) 95 k[j] = data[j]; 96 for (; j < 128; j++) 97 k[j] = Sbox[(k[j - len] + k[j - 1]) & 0xff]; 98 99 T8 = (bits + 7) / 8; 100 j = (8*T8 - bits); 101 TM = 0xff >> j; 102 103 k[128 - T8] = Sbox[k[128 - T8] & TM]; 104 105 for (j = 127 - T8; j >= 0; j--) 106 k[j] = Sbox[k[j + 1] ^ k[j + T8]]; 107 108 for (j = 0; j < 64; j++) 109 key->data[j] = k[(j * 2) + 0] | (k[(j * 2) + 1] << 8); 110 memset(k, 0, sizeof(k)); 111} 112 113#define ROT16L(w,n) ((w<<n)|(w>>(16-n))) 114#define ROT16R(w,n) ((w>>n)|(w<<(16-n))) 115 116void 117RC2_encryptc(unsigned char *in, unsigned char *out, const RC2_KEY *key) 118{ 119 int i, j; 120 int w0, w1, w2, w3; 121 int t0, t1, t2, t3; 122 123 w0 = in[0] | (in[1] << 8); 124 w1 = in[2] | (in[3] << 8); 125 w2 = in[4] | (in[5] << 8); 126 w3 = in[6] | (in[7] << 8); 127 128 for (i = 0; i < 16; i++) { 129 j = i * 4; 130 t0 = (w0 + (w1 & ~w3) + (w2 & w3) + key->data[j + 0]) & 0xffff; 131 w0 = ROT16L(t0, 1); 132 t1 = (w1 + (w2 & ~w0) + (w3 & w0) + key->data[j + 1]) & 0xffff; 133 w1 = ROT16L(t1, 2); 134 t2 = (w2 + (w3 & ~w1) + (w0 & w1) + key->data[j + 2]) & 0xffff; 135 w2 = ROT16L(t2, 3); 136 t3 = (w3 + (w0 & ~w2) + (w1 & w2) + key->data[j + 3]) & 0xffff; 137 w3 = ROT16L(t3, 5); 138 if(i == 4 || i == 10) { 139 w0 += key->data[w3 & 63]; 140 w1 += key->data[w0 & 63]; 141 w2 += key->data[w1 & 63]; 142 w3 += key->data[w2 & 63]; 143 } 144 } 145 146 out[0] = w0 & 0xff; 147 out[1] = (w0 >> 8) & 0xff; 148 out[2] = w1 & 0xff; 149 out[3] = (w1 >> 8) & 0xff; 150 out[4] = w2 & 0xff; 151 out[5] = (w2 >> 8) & 0xff; 152 out[6] = w3 & 0xff; 153 out[7] = (w3 >> 8) & 0xff; 154} 155 156void 157RC2_decryptc(unsigned char *in, unsigned char *out, const RC2_KEY *key) 158{ 159 int i, j; 160 int w0, w1, w2, w3; 161 int t0, t1, t2, t3; 162 163 w0 = in[0] | (in[1] << 8); 164 w1 = in[2] | (in[3] << 8); 165 w2 = in[4] | (in[5] << 8); 166 w3 = in[6] | (in[7] << 8); 167 168 for (i = 15; i >= 0; i--) { 169 j = i * 4; 170 171 if(i == 4 || i == 10) { 172 w3 = (w3 - key->data[w2 & 63]) & 0xffff; 173 w2 = (w2 - key->data[w1 & 63]) & 0xffff; 174 w1 = (w1 - key->data[w0 & 63]) & 0xffff; 175 w0 = (w0 - key->data[w3 & 63]) & 0xffff; 176 } 177 178 t3 = ROT16R(w3, 5); 179 w3 = (t3 - (w0 & ~w2) - (w1 & w2) - key->data[j + 3]) & 0xffff; 180 t2 = ROT16R(w2, 3); 181 w2 = (t2 - (w3 & ~w1) - (w0 & w1) - key->data[j + 2]) & 0xffff; 182 t1 = ROT16R(w1, 2); 183 w1 = (t1 - (w2 & ~w0) - (w3 & w0) - key->data[j + 1]) & 0xffff; 184 t0 = ROT16R(w0, 1); 185 w0 = (t0 - (w1 & ~w3) - (w2 & w3) - key->data[j + 0]) & 0xffff; 186 187 } 188 out[0] = w0 & 0xff; 189 out[1] = (w0 >> 8) & 0xff; 190 out[2] = w1 & 0xff; 191 out[3] = (w1 >> 8) & 0xff; 192 out[4] = w2 & 0xff; 193 out[5] = (w2 >> 8) & 0xff; 194 out[6] = w3 & 0xff; 195 out[7] = (w3 >> 8) & 0xff; 196} 197 198void 199RC2_cbc_encrypt(const unsigned char *in, unsigned char *out, long size, 200 RC2_KEY *key, unsigned char *iv, int forward_encrypt) 201{ 202 unsigned char tmp[RC2_BLOCK_SIZE]; 203 int i; 204 205 if (forward_encrypt) { 206 while (size >= RC2_BLOCK_SIZE) { 207 for (i = 0; i < RC2_BLOCK_SIZE; i++) 208 tmp[i] = in[i] ^ iv[i]; 209 RC2_encryptc(tmp, out, key); 210 memcpy(iv, out, RC2_BLOCK_SIZE); 211 size -= RC2_BLOCK_SIZE; 212 in += RC2_BLOCK_SIZE; 213 out += RC2_BLOCK_SIZE; 214 } 215 if (size) { 216 for (i = 0; i < size; i++) 217 tmp[i] = in[i] ^ iv[i]; 218 for (i = size; i < RC2_BLOCK_SIZE; i++) 219 tmp[i] = iv[i]; 220 RC2_encryptc(tmp, out, key); 221 memcpy(iv, out, RC2_BLOCK_SIZE); 222 } 223 } else { 224 while (size >= RC2_BLOCK_SIZE) { 225 memcpy(tmp, in, RC2_BLOCK_SIZE); 226 RC2_decryptc(tmp, out, key); 227 for (i = 0; i < RC2_BLOCK_SIZE; i++) 228 out[i] ^= iv[i]; 229 memcpy(iv, tmp, RC2_BLOCK_SIZE); 230 size -= RC2_BLOCK_SIZE; 231 in += RC2_BLOCK_SIZE; 232 out += RC2_BLOCK_SIZE; 233 } 234 if (size) { 235 memcpy(tmp, in, RC2_BLOCK_SIZE); 236 RC2_decryptc(tmp, out, key); 237 for (i = 0; i < size; i++) 238 out[i] ^= iv[i]; 239 memcpy(iv, tmp, RC2_BLOCK_SIZE); 240 } 241 } 242} 243