2 * A 32-bit implementation of the TEA algorithm
3 * Copyright (c) 2015 Vesselin Bontchev
5 * Loosely based on the implementation of David Wheeler and Roger Needham,
6 * https://en.wikipedia.org/wiki/Tiny_Encryption_Algorithm#Reference_code
8 * This file is part of FFmpeg.
10 * FFmpeg is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU Lesser General Public
12 * License as published by the Free Software Foundation; either
13 * version 2.1 of the License, or (at your option) any later version.
15 * FFmpeg is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * Lesser General Public License for more details.
20 * You should have received a copy of the GNU Lesser General Public
21 * License along with FFmpeg; if not, write to the Free Software
22 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
27 #include "intreadwrite.h"
30 typedef struct AVTEA {
35 struct AVTEA *av_tea_alloc(void)
37 return av_mallocz(sizeof(struct AVTEA));
40 const int av_tea_size = sizeof(AVTEA);
42 void av_tea_init(AVTEA *ctx, const uint8_t key[16], int rounds)
46 for (i = 0; i < 4; i++)
47 ctx->key[i] = AV_RB32(key + (i << 2));
52 static void tea_crypt_ecb(AVTEA *ctx, uint8_t *dst, const uint8_t *src,
53 int decrypt, uint8_t *iv)
56 int rounds = ctx->rounds;
57 uint32_t k0, k1, k2, k3;
64 v1 = AV_RB32(src + 4);
68 uint32_t delta = 0x9E3779B9U, sum = delta * (rounds / 2);
70 for (i = 0; i < rounds / 2; i++) {
71 v1 -= ((v0 << 4) + k2) ^ (v0 + sum) ^ ((v0 >> 5) + k3);
72 v0 -= ((v1 << 4) + k0) ^ (v1 + sum) ^ ((v1 >> 5) + k1);
77 v1 ^= AV_RB32(iv + 4);
82 uint32_t sum = 0, delta = 0x9E3779B9U;
84 for (i = 0; i < rounds / 2; i++) {
86 v0 += ((v1 << 4) + k0) ^ (v1 + sum) ^ ((v1 >> 5) + k1);
87 v1 += ((v0 << 4) + k2) ^ (v0 + sum) ^ ((v0 >> 5) + k3);
95 void av_tea_crypt(AVTEA *ctx, uint8_t *dst, const uint8_t *src, int count,
96 uint8_t *iv, int decrypt)
102 tea_crypt_ecb(ctx, dst, src, decrypt, iv);
110 for (i = 0; i < 8; i++)
111 dst[i] = src[i] ^ iv[i];
112 tea_crypt_ecb(ctx, dst, dst, decrypt, NULL);
115 tea_crypt_ecb(ctx, dst, src, decrypt, NULL);
126 #define TEA_NUM_TESTS 4
128 // https://github.com/logandrews/TeaCrypt/blob/master/tea/tea_test.go
129 static const uint8_t tea_test_key[TEA_NUM_TESTS][16] = {
130 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
131 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
133 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
134 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
136 { 0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,
137 0x88, 0x99, 0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF
139 { 0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,
140 0x88, 0x99, 0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF
144 static const uint8_t tea_test_pt[TEA_NUM_TESTS][8] = {
145 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
146 { 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08 },
147 { 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08 },
148 { 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF }
151 static const uint8_t tea_test_ct[TEA_NUM_TESTS][8] = {
152 { 0x41, 0xEA, 0x3A, 0x0A, 0x94, 0xBA, 0xA9, 0x40 },
153 { 0x6A, 0x2F, 0x9C, 0xF3, 0xFC, 0xCF, 0x3C, 0x55 },
154 { 0xDE, 0xB1, 0xC0, 0xA2, 0x7E, 0x74, 0x5D, 0xB3 },
155 { 0x12, 0x6C, 0x6B, 0x92, 0xC0, 0x65, 0x3A, 0x3E }
158 static void test_tea(AVTEA *ctx, uint8_t *dst, const uint8_t *src,
159 const uint8_t *ref, int len, uint8_t *iv, int dir,
162 av_tea_crypt(ctx, dst, src, len, iv, dir);
163 if (memcmp(dst, ref, 8*len)) {
165 printf("%s failed\ngot ", test);
166 for (i = 0; i < 8*len; i++)
167 printf("%02x ", dst[i]);
168 printf("\nexpected ");
169 for (i = 0; i < 8*len; i++)
170 printf("%02x ", ref[i]);
179 uint8_t buf[8], iv[8];
181 static const uint8_t src[32] = "HelloWorldHelloWorldHelloWorld";
185 ctx = av_tea_alloc();
189 for (i = 0; i < TEA_NUM_TESTS; i++) {
190 av_tea_init(ctx, tea_test_key[i], 64);
192 test_tea(ctx, buf, tea_test_pt[i], tea_test_ct[i], 1, NULL, 0, "encryption");
193 test_tea(ctx, buf, tea_test_ct[i], tea_test_pt[i], 1, NULL, 1, "decryption");
196 memcpy(iv, "HALLO123", 8);
197 av_tea_crypt(ctx, ct, src, 4, iv, 0);
199 /* decrypt into pl */
200 memcpy(iv, "HALLO123", 8);
201 test_tea(ctx, pl, ct, src, 4, iv, 1, "CBC decryption");
203 memcpy(iv, "HALLO123", 8);
204 test_tea(ctx, ct, ct, src, 4, iv, 1, "CBC inplace decryption");
207 printf("Test encryption/decryption success.\n");