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 FFmpeg.
9 * FFmpeg 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 * FFmpeg 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 FFmpeg; 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)
42 uint32_t k0 = ctx->key[0];
43 uint32_t k1 = ctx->key[1];
44 uint32_t k2 = ctx->key[2];
45 uint32_t k3 = ctx->key[3];
48 v1 = AV_RB32(src + 4);
53 uint32_t delta = 0x9E3779B9U, sum = delta * 32;
55 for (i = 0; i < 32; i++) {
56 v1 -= (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + ctx->key[(sum >> 11) & 3]);
58 v0 -= (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + ctx->key[sum & 3]);
61 #define DSTEP(SUM, K0, K1) \
62 v1 -= (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (SUM + K0); \
63 v0 -= (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (SUM - 0x9E3779B9U + K1)
65 DSTEP(0xC6EF3720U, k2, k3);
66 DSTEP(0x28B7BD67U, k3, k2);
67 DSTEP(0x8A8043AEU, k0, k1);
68 DSTEP(0xEC48C9F5U, k1, k0);
69 DSTEP(0x4E11503CU, k2, k3);
70 DSTEP(0xAFD9D683U, k2, k2);
71 DSTEP(0x11A25CCAU, k3, k1);
72 DSTEP(0x736AE311U, k0, k0);
73 DSTEP(0xD5336958U, k1, k3);
74 DSTEP(0x36FBEF9FU, k1, k2);
75 DSTEP(0x98C475E6U, k2, k1);
76 DSTEP(0xFA8CFC2DU, k3, k0);
77 DSTEP(0x5C558274U, k0, k3);
78 DSTEP(0xBE1E08BBU, k1, k2);
79 DSTEP(0x1FE68F02U, k1, k1);
80 DSTEP(0x81AF1549U, k2, k0);
81 DSTEP(0xE3779B90U, k3, k3);
82 DSTEP(0x454021D7U, k0, k2);
83 DSTEP(0xA708A81EU, k1, k1);
84 DSTEP(0x08D12E65U, k1, k0);
85 DSTEP(0x6A99B4ACU, k2, k3);
86 DSTEP(0xCC623AF3U, k3, k2);
87 DSTEP(0x2E2AC13AU, k0, k1);
88 DSTEP(0x8FF34781U, k0, k0);
89 DSTEP(0xF1BBCDC8U, k1, k3);
90 DSTEP(0x5384540FU, k2, k2);
91 DSTEP(0xB54CDA56U, k3, k1);
92 DSTEP(0x1715609DU, k0, k0);
93 DSTEP(0x78DDE6E4U, k0, k3);
94 DSTEP(0xDAA66D2BU, k1, k2);
95 DSTEP(0x3C6EF372U, k2, k1);
96 DSTEP(0x9E3779B9U, k3, k0);
100 v1 ^= AV_RB32(iv + 4);
106 uint32_t sum = 0, delta = 0x9E3779B9U;
108 for (i = 0; i < 32; i++) {
109 v0 += (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + ctx->key[sum & 3]);
111 v1 += (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + ctx->key[(sum >> 11) & 3]);
114 #define ESTEP(SUM, K0, K1) \
115 v0 += (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (SUM + K0);\
116 v1 += (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (SUM + 0x9E3779B9U + K1)
117 ESTEP(0x00000000U, k0, k3);
118 ESTEP(0x9E3779B9U, k1, k2);
119 ESTEP(0x3C6EF372U, k2, k1);
120 ESTEP(0xDAA66D2BU, k3, k0);
121 ESTEP(0x78DDE6E4U, k0, k0);
122 ESTEP(0x1715609DU, k1, k3);
123 ESTEP(0xB54CDA56U, k2, k2);
124 ESTEP(0x5384540FU, k3, k1);
125 ESTEP(0xF1BBCDC8U, k0, k0);
126 ESTEP(0x8FF34781U, k1, k0);
127 ESTEP(0x2E2AC13AU, k2, k3);
128 ESTEP(0xCC623AF3U, k3, k2);
129 ESTEP(0x6A99B4ACU, k0, k1);
130 ESTEP(0x08D12E65U, k1, k1);
131 ESTEP(0xA708A81EU, k2, k0);
132 ESTEP(0x454021D7U, k3, k3);
133 ESTEP(0xE3779B90U, k0, k2);
134 ESTEP(0x81AF1549U, k1, k1);
135 ESTEP(0x1FE68F02U, k2, k1);
136 ESTEP(0xBE1E08BBU, k3, k0);
137 ESTEP(0x5C558274U, k0, k3);
138 ESTEP(0xFA8CFC2DU, k1, k2);
139 ESTEP(0x98C475E6U, k2, k1);
140 ESTEP(0x36FBEF9FU, k3, k1);
141 ESTEP(0xD5336958U, k0, k0);
142 ESTEP(0x736AE311U, k1, k3);
143 ESTEP(0x11A25CCAU, k2, k2);
144 ESTEP(0xAFD9D683U, k3, k2);
145 ESTEP(0x4E11503CU, k0, k1);
146 ESTEP(0xEC48C9F5U, k1, k0);
147 ESTEP(0x8A8043AEU, k2, k3);
148 ESTEP(0x28B7BD67U, k3, k2);
153 AV_WB32(dst + 4, v1);
156 void av_xtea_crypt(AVXTEA *ctx, uint8_t *dst, const uint8_t *src, int count,
157 uint8_t *iv, int decrypt)
163 xtea_crypt_ecb(ctx, dst, src, decrypt, iv);
171 for (i = 0; i < 8; i++)
172 dst[i] = src[i] ^ iv[i];
173 xtea_crypt_ecb(ctx, dst, dst, decrypt, NULL);
176 xtea_crypt_ecb(ctx, dst, src, decrypt, NULL);
187 #define XTEA_NUM_TESTS 6
189 static const uint8_t xtea_test_key[XTEA_NUM_TESTS][16] = {
190 { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
191 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f },
192 { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
193 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f },
194 { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
195 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f },
196 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
197 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
198 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
199 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
200 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
201 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }
204 static const uint8_t xtea_test_pt[XTEA_NUM_TESTS][8] = {
205 { 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48 },
206 { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
207 { 0x5a, 0x5b, 0x6e, 0x27, 0x89, 0x48, 0xd7, 0x7f },
208 { 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48 },
209 { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
210 { 0x70, 0xe1, 0x22, 0x5d, 0x6e, 0x4e, 0x76, 0x55 }
213 static const uint8_t xtea_test_ct[XTEA_NUM_TESTS][8] = {
214 { 0x49, 0x7d, 0xf3, 0xd0, 0x72, 0x61, 0x2c, 0xb5 },
215 { 0xe7, 0x8f, 0x2d, 0x13, 0x74, 0x43, 0x41, 0xd8 },
216 { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
217 { 0xa0, 0x39, 0x05, 0x89, 0xf8, 0xb8, 0xef, 0xa5 },
218 { 0xed, 0x23, 0x37, 0x5a, 0x82, 0x1a, 0x8c, 0x2d },
219 { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 }
222 static void test_xtea(AVXTEA *ctx, uint8_t *dst, const uint8_t *src,
223 const uint8_t *ref, int len, uint8_t *iv, int dir,
226 av_xtea_crypt(ctx, dst, src, len, iv, dir);
227 if (memcmp(dst, ref, 8*len)) {
229 printf("%s failed\ngot ", test);
230 for (i = 0; i < 8*len; i++)
231 printf("%02x ", dst[i]);
232 printf("\nexpected ");
233 for (i = 0; i < 8*len; i++)
234 printf("%02x ", ref[i]);
243 uint8_t buf[8], iv[8];
245 const uint8_t src[32] = "HelloWorldHelloWorldHelloWorld";
249 for (i = 0; i < XTEA_NUM_TESTS; i++) {
250 av_xtea_init(&ctx, xtea_test_key[i]);
252 test_xtea(&ctx, buf, xtea_test_pt[i], xtea_test_ct[i], 1, NULL, 0, "encryption");
253 test_xtea(&ctx, buf, xtea_test_ct[i], xtea_test_pt[i], 1, NULL, 1, "decryption");
256 memcpy(iv, "HALLO123", 8);
257 av_xtea_crypt(&ctx, ct, src, 4, iv, 0);
259 /* decrypt into pl */
260 memcpy(iv, "HALLO123", 8);
261 test_xtea(&ctx, pl, ct, src, 4, iv, 1, "CBC decryption");
263 memcpy(iv, "HALLO123", 8);
264 test_xtea(&ctx, ct, ct, src, 4, iv, 1, "CBC inplace decryption");
267 printf("Test encryption/decryption success.\n");