From 323ec6b5e21433d32d0b5a8d187d0396734d3ddf Mon Sep 17 00:00:00 2001 From: Vesselin Bontchev Date: Sun, 19 Jul 2015 22:25:53 +0200 Subject: [PATCH] Add support for TEA (Tiny Encryption Algorithm) Signed-off-by: Michael Niedermayer --- libavutil/Makefile | 3 + libavutil/tea.c | 213 +++++++++++++++++++++++++++++++++++++++ libavutil/tea.h | 71 +++++++++++++ tests/fate/libavutil.mak | 4 + tests/ref/fate/tea | 1 + 5 files changed, 292 insertions(+) create mode 100644 libavutil/tea.c create mode 100644 libavutil/tea.h create mode 100644 tests/ref/fate/tea diff --git a/libavutil/Makefile b/libavutil/Makefile index 6fa810e744..70f8bae0a6 100644 --- a/libavutil/Makefile +++ b/libavutil/Makefile @@ -63,6 +63,7 @@ HEADERS = adler32.h \ twofish.h \ version.h \ xtea.h \ + tea.h \ HEADERS-$(CONFIG_LZO) += lzo.h @@ -135,6 +136,7 @@ OBJS = adler32.o \ utils.o \ xga_font_data.o \ xtea.o \ + tea.o \ OBJS-$(!HAVE_ATOMICS_NATIVE) += atomic.o \ @@ -192,6 +194,7 @@ TESTPROGS = adler32 \ twofish \ utf8 \ xtea \ + tea \ TESTPROGS-$(HAVE_LZO1X_999_COMPRESS) += lzo diff --git a/libavutil/tea.c b/libavutil/tea.c new file mode 100644 index 0000000000..bf767188f4 --- /dev/null +++ b/libavutil/tea.c @@ -0,0 +1,213 @@ +/* + * A 32-bit implementation of the TEA algorithm + * Copyright (c) 2015 Vesselin Bontchev + * + * Loosely based on the implementation of David Wheeler and Roger Needham, + * https://en.wikipedia.org/wiki/Tiny_Encryption_Algorithm#Reference_code + * + * This file is part of FFmpeg. + * + * FFmpeg is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * FFmpeg is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with FFmpeg; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include "avutil.h" +#include "common.h" +#include "intreadwrite.h" +#include "tea.h" + +typedef struct AVTEA { + uint32_t key[16]; + int rounds; +} AVTEA; + +struct AVTEA *av_tea_alloc(void) +{ + return av_mallocz(sizeof(struct AVTEA)); +} + +const int av_tea_size = sizeof(AVTEA); + +void av_tea_init(AVTEA *ctx, const uint8_t key[16], int rounds) +{ + int i; + + for (i = 0; i < 4; i++) + ctx->key[i] = AV_RB32(key + (i << 2)); + + ctx->rounds = rounds; +} + +static void tea_crypt_ecb(AVTEA *ctx, uint8_t *dst, const uint8_t *src, + int decrypt, uint8_t *iv) +{ + uint32_t v0, v1; + int rounds = ctx->rounds; + uint32_t k0, k1, k2, k3; + k0 = ctx->key[0]; + k1 = ctx->key[1]; + k2 = ctx->key[2]; + k3 = ctx->key[3]; + + v0 = AV_RB32(src); + v1 = AV_RB32(src + 4); + + if (decrypt) { + int i; + uint32_t delta = 0x9E3779B9U, sum = delta * (rounds / 2); + + for (i = 0; i < rounds / 2; i++) { + v1 -= ((v0 << 4) + k2) ^ (v0 + sum) ^ ((v0 >> 5) + k3); + v0 -= ((v1 << 4) + k0) ^ (v1 + sum) ^ ((v1 >> 5) + k1); + sum -= delta; + } + if (iv) { + v0 ^= AV_RB32(iv); + v1 ^= AV_RB32(iv + 4); + memcpy(iv, src, 8); + } + } else { + int i; + uint32_t sum = 0, delta = 0x9E3779B9U; + + for (i = 0; i < rounds / 2; i++) { + sum += delta; + v0 += ((v1 << 4) + k0) ^ (v1 + sum) ^ ((v1 >> 5) + k1); + v1 += ((v0 << 4) + k2) ^ (v0 + sum) ^ ((v0 >> 5) + k3); + } + } + + AV_WB32(dst, v0); + AV_WB32(dst + 4, v1); +} + +void av_tea_crypt(AVTEA *ctx, uint8_t *dst, const uint8_t *src, int count, + uint8_t *iv, int decrypt) +{ + int i; + + if (decrypt) { + while (count--) { + tea_crypt_ecb(ctx, dst, src, decrypt, iv); + + src += 8; + dst += 8; + } + } else { + while (count--) { + if (iv) { + for (i = 0; i < 8; i++) + dst[i] = src[i] ^ iv[i]; + tea_crypt_ecb(ctx, dst, dst, decrypt, NULL); + memcpy(iv, dst, 8); + } else { + tea_crypt_ecb(ctx, dst, src, decrypt, NULL); + } + src += 8; + dst += 8; + } + } +} + +#ifdef TEST +#include + +#define TEA_NUM_TESTS 4 + +// https://github.com/logandrews/TeaCrypt/blob/master/tea/tea_test.go +static const uint8_t tea_test_key[TEA_NUM_TESTS][16] = { + { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 + }, + { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 + }, + { 0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, + 0x88, 0x99, 0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF + }, + { 0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, + 0x88, 0x99, 0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF + } +}; + +static const uint8_t tea_test_pt[TEA_NUM_TESTS][8] = { + { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }, + { 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08 }, + { 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08 }, + { 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF } +}; + +static const uint8_t tea_test_ct[TEA_NUM_TESTS][8] = { + { 0x41, 0xEA, 0x3A, 0x0A, 0x94, 0xBA, 0xA9, 0x40 }, + { 0x6A, 0x2F, 0x9C, 0xF3, 0xFC, 0xCF, 0x3C, 0x55 }, + { 0xDE, 0xB1, 0xC0, 0xA2, 0x7E, 0x74, 0x5D, 0xB3 }, + { 0x12, 0x6C, 0x6B, 0x92, 0xC0, 0x65, 0x3A, 0x3E } +}; + +static void test_tea(AVTEA *ctx, uint8_t *dst, const uint8_t *src, + const uint8_t *ref, int len, uint8_t *iv, int dir, + const char *test) +{ + av_tea_crypt(ctx, dst, src, len, iv, dir); + if (memcmp(dst, ref, 8*len)) { + int i; + printf("%s failed\ngot ", test); + for (i = 0; i < 8*len; i++) + printf("%02x ", dst[i]); + printf("\nexpected "); + for (i = 0; i < 8*len; i++) + printf("%02x ", ref[i]); + printf("\n"); + exit(1); + } +} + +int main(void) +{ + AVTEA *ctx; + uint8_t buf[8], iv[8]; + int i; + static const uint8_t src[32] = "HelloWorldHelloWorldHelloWorld"; + uint8_t ct[32]; + uint8_t pl[32]; + + ctx = av_tea_alloc(); + if (!ctx) + return 1; + + for (i = 0; i < TEA_NUM_TESTS; i++) { + av_tea_init(ctx, tea_test_key[i], 64); + + test_tea(ctx, buf, tea_test_pt[i], tea_test_ct[i], 1, NULL, 0, "encryption"); + test_tea(ctx, buf, tea_test_ct[i], tea_test_pt[i], 1, NULL, 1, "decryption"); + + /* encrypt */ + memcpy(iv, "HALLO123", 8); + av_tea_crypt(ctx, ct, src, 4, iv, 0); + + /* decrypt into pl */ + memcpy(iv, "HALLO123", 8); + test_tea(ctx, pl, ct, src, 4, iv, 1, "CBC decryption"); + + memcpy(iv, "HALLO123", 8); + test_tea(ctx, ct, ct, src, 4, iv, 1, "CBC inplace decryption"); + } + + printf("Test encryption/decryption success.\n"); + av_free(ctx); + + return 0; +} + +#endif diff --git a/libavutil/tea.h b/libavutil/tea.h new file mode 100644 index 0000000000..dd929bdafd --- /dev/null +++ b/libavutil/tea.h @@ -0,0 +1,71 @@ +/* + * A 32-bit implementation of the TEA algorithm + * Copyright (c) 2015 Vesselin Bontchev + * + * This file is part of FFmpeg. + * + * FFmpeg is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * FFmpeg is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with FFmpeg; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#ifndef AVUTIL_TEA_H +#define AVUTIL_TEA_H + +#include + +/** + * @file + * @brief Public header for libavutil TEA algorithm + * @defgroup lavu_tea TEA + * @ingroup lavu_crypto + * @{ + */ + +extern const int av_tea_size; + +struct AVTEA; + +/** + * Allocate an AVTEA context + * To free the struct: av_free(ptr) + */ +struct AVTEA *av_tea_alloc(void); + +/** + * Initialize an AVTEA context. + * + * @param ctx an AVTEA context + * @param key a key of 16 bytes used for encryption/decryption + * @param rounds the number of rounds in TEA (64 is the "standard") + */ +void av_tea_init(struct AVTEA *ctx, const uint8_t key[16], int rounds); + +/** + * Encrypt or decrypt a buffer using a previously initialized context. + * + * @param ctx an AVTEA context + * @param dst destination array, can be equal to src + * @param src source array, can be equal to dst + * @param count number of 8 byte blocks + * @param iv initialization vector for CBC mode, if NULL then ECB will be used + * @param decrypt 0 for encryption, 1 for decryption + */ +void av_tea_crypt(struct AVTEA *ctx, uint8_t *dst, const uint8_t *src, + int count, uint8_t *iv, int decrypt); + +/** + * @} + */ + +#endif /* AVUTIL_TEA_H */ diff --git a/tests/fate/libavutil.mak b/tests/fate/libavutil.mak index ff052e060d..022ae6ad15 100644 --- a/tests/fate/libavutil.mak +++ b/tests/fate/libavutil.mak @@ -121,6 +121,10 @@ FATE_LIBAVUTIL += fate-xtea fate-xtea: libavutil/xtea-test$(EXESUF) fate-xtea: CMD = run libavutil/xtea-test +FATE_LIBAVUTIL += fate-tea +fate-tea: libavutil/tea-test$(EXESUF) +fate-tea: CMD = run libavutil/tea-test + FATE_LIBAVUTIL += fate-opt fate-opt: libavutil/opt-test$(EXESUF) fate-opt: CMD = run libavutil/opt-test diff --git a/tests/ref/fate/tea b/tests/ref/fate/tea new file mode 100644 index 0000000000..fed0b4dd3b --- /dev/null +++ b/tests/ref/fate/tea @@ -0,0 +1 @@ +Test encryption/decryption success.