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,
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]);
56 uint32_t sum = 0, delta = 0x9E3779B9;
58 for (i = 0; i < 32; i++) {
59 v0 += (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + ctx->key[sum & 3]);
61 v1 += (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + ctx->key[(sum >> 11) & 3]);
69 void av_xtea_crypt(AVXTEA *ctx, uint8_t *dst, const uint8_t *src, int count,
70 uint8_t *iv, int decrypt)
76 xtea_crypt_ecb(ctx, dst, src, decrypt);
79 for (i = 0; i < 8; i++)
80 dst[i] = dst[i] ^ iv[i];
85 for (i = 0; i < 8; i++)
86 dst[i] = src[i] ^ iv[i];
87 xtea_crypt_ecb(ctx, dst, dst, decrypt);
90 xtea_crypt_ecb(ctx, dst, src, decrypt);
104 #define XTEA_NUM_TESTS 6
106 static const uint8_t xtea_test_key[XTEA_NUM_TESTS][16] = {
107 { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
108 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f },
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, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
114 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
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 }
121 static const uint8_t xtea_test_pt[XTEA_NUM_TESTS][8] = {
122 { 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48 },
123 { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
124 { 0x5a, 0x5b, 0x6e, 0x27, 0x89, 0x48, 0xd7, 0x7f },
125 { 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48 },
126 { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
127 { 0x70, 0xe1, 0x22, 0x5d, 0x6e, 0x4e, 0x76, 0x55 }
130 static const uint8_t xtea_test_ct[XTEA_NUM_TESTS][8] = {
131 { 0x49, 0x7d, 0xf3, 0xd0, 0x72, 0x61, 0x2c, 0xb5 },
132 { 0xe7, 0x8f, 0x2d, 0x13, 0x74, 0x43, 0x41, 0xd8 },
133 { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
134 { 0xa0, 0x39, 0x05, 0x89, 0xf8, 0xb8, 0xef, 0xa5 },
135 { 0xed, 0x23, 0x37, 0x5a, 0x82, 0x1a, 0x8c, 0x2d },
136 { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 }
145 for (i = 0; i < XTEA_NUM_TESTS; i++) {
146 av_xtea_init(&ctx, xtea_test_key[i]);
148 av_xtea_crypt(&ctx, buf, xtea_test_pt[i], 1, NULL, 0);
149 if (memcmp(buf, xtea_test_ct[i], 8)) {
150 printf("Test encryption failed.\n");
154 av_xtea_crypt(&ctx, buf, xtea_test_ct[i], 1, NULL, 1);
155 if (memcmp(buf, xtea_test_pt[i], 8)) {
156 printf("Test decryption failed.\n");
160 printf("Test encryption/decryption success.\n");