2 * A 32-bit implementation of the XTEA algorithm
3 * Copyright (c) 2012 Samuel Pitoiset
5 * loosely based on the implementation of David Wheeler and Roger Needham
7 * This file is part of Libav.
9 * Libav is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU Lesser General Public
11 * License as published by the Free Software Foundation; either
12 * version 2.1 of the License, or (at your option) any later version.
14 * Libav is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * Lesser General Public License for more details.
19 * You should have received a copy of the GNU Lesser General Public
20 * License along with Libav; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
24 #include "libavutil/intreadwrite.h"
30 void av_xtea_init(AVXTEA *ctx, const uint8_t key[16])
34 for (i = 0; i < 4; i++)
35 ctx->key[i] = AV_RB32(key + (i << 2));
38 static void xtea_crypt_ecb(AVXTEA *ctx, uint8_t *dst, const uint8_t *src,
39 int decrypt, uint8_t *iv)
45 v1 = AV_RB32(src + 4);
48 uint32_t delta = 0x9E3779B9, sum = delta * 32;
50 for (i = 0; i < 32; i++) {
51 v1 -= (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + ctx->key[(sum >> 11) & 3]);
53 v0 -= (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + ctx->key[sum & 3]);
57 v1 ^= AV_RB32(iv + 4);
61 uint32_t sum = 0, delta = 0x9E3779B9;
63 for (i = 0; i < 32; i++) {
64 v0 += (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + ctx->key[sum & 3]);
66 v1 += (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + ctx->key[(sum >> 11) & 3]);
74 void av_xtea_crypt(AVXTEA *ctx, uint8_t *dst, const uint8_t *src, int count,
75 uint8_t *iv, int decrypt)
81 xtea_crypt_ecb(ctx, dst, src, decrypt, iv);
89 for (i = 0; i < 8; i++)
90 dst[i] = src[i] ^ iv[i];
91 xtea_crypt_ecb(ctx, dst, dst, decrypt, NULL);
94 xtea_crypt_ecb(ctx, dst, src, decrypt, NULL);
106 #define XTEA_NUM_TESTS 6
108 static const uint8_t xtea_test_key[XTEA_NUM_TESTS][16] = {
109 { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
110 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f },
111 { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
112 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f },
113 { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
114 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f },
115 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
116 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
117 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
118 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
119 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
120 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }
123 static const uint8_t xtea_test_pt[XTEA_NUM_TESTS][8] = {
124 { 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48 },
125 { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
126 { 0x5a, 0x5b, 0x6e, 0x27, 0x89, 0x48, 0xd7, 0x7f },
127 { 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48 },
128 { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
129 { 0x70, 0xe1, 0x22, 0x5d, 0x6e, 0x4e, 0x76, 0x55 }
132 static const uint8_t xtea_test_ct[XTEA_NUM_TESTS][8] = {
133 { 0x49, 0x7d, 0xf3, 0xd0, 0x72, 0x61, 0x2c, 0xb5 },
134 { 0xe7, 0x8f, 0x2d, 0x13, 0x74, 0x43, 0x41, 0xd8 },
135 { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
136 { 0xa0, 0x39, 0x05, 0x89, 0xf8, 0xb8, 0xef, 0xa5 },
137 { 0xed, 0x23, 0x37, 0x5a, 0x82, 0x1a, 0x8c, 0x2d },
138 { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 }
142 static void test_xtea(AVXTEA *ctx, uint8_t *dst, const uint8_t *src,
143 const uint8_t *ref, int len, uint8_t *iv, int dir,
146 av_xtea_crypt(ctx, dst, src, len, iv, dir);
147 if (memcmp(dst, ref, 8*len)) {
149 printf("%s failed\ngot ", test);
150 for (i = 0; i < 8*len; i++)
151 printf("%02x ", dst[i]);
152 printf("\nexpected ");
153 for (i = 0; i < 8*len; i++)
154 printf("%02x ", ref[i]);
166 for (i = 0; i < XTEA_NUM_TESTS; i++) {
167 av_xtea_init(&ctx, xtea_test_key[i]);
169 test_xtea(&ctx, buf, xtea_test_pt[i], xtea_test_ct[i], 1, NULL, 0, "encryption");
170 test_xtea(&ctx, buf, xtea_test_ct[i], xtea_test_pt[i], 1, NULL, 1, "decryption");
172 printf("Test encryption/decryption success.\n");