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FFmpeg/libavutil/xtea.c
James Almer 3d1690b8c6 avutil: undo FF_API_CRYPTO_CONTEXT deprecation 
It's been argued that the benefits of the current implementation far outweight
those of making the structs opaque.

This deprecation is not present in any release, so it can be safely removed.

Reviewed-by: Ronald S. Bultje <rsbultje@gmail.com>
Signed-off-by: James Almer <jamrial@gmail.com>
2015-10-16 19:13:38 -03:00

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/*
* A 32-bit implementation of the XTEA algorithm
* Copyright (c) 2012 Samuel Pitoiset
*
* loosely based on the implementation of David Wheeler and Roger Needham
*
* 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
*/
/**
* @file
* @brief XTEA 32-bit implementation
* @author Samuel Pitoiset
* @ingroup lavu_xtea
*/
#include "avutil.h"
#include "common.h"
#include "intreadwrite.h"
#include "mem.h"
#include "xtea.h"
AVXTEA *av_xtea_alloc(void)
{
return av_mallocz(sizeof(struct AVXTEA));
}
void av_xtea_init(AVXTEA *ctx, const uint8_t key[16])
{
int i;
for (i = 0; i < 4; i++)
ctx->key[i] = AV_RB32(key + (i << 2));
}
static void xtea_crypt_ecb(AVXTEA *ctx, uint8_t *dst, const uint8_t *src,
int decrypt, uint8_t *iv)
{
uint32_t v0, v1;
#if !CONFIG_SMALL
uint32_t k0 = ctx->key[0];
uint32_t k1 = ctx->key[1];
uint32_t k2 = ctx->key[2];
uint32_t k3 = ctx->key[3];
#endif
v0 = AV_RB32(src);
v1 = AV_RB32(src + 4);
if (decrypt) {
#if CONFIG_SMALL
int i;
uint32_t delta = 0x9E3779B9U, sum = delta * 32;
for (i = 0; i < 32; i++) {
v1 -= (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + ctx->key[(sum >> 11) & 3]);
sum -= delta;
v0 -= (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + ctx->key[sum & 3]);
}
#else
#define DSTEP(SUM, K0, K1) \
v1 -= (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (SUM + K0); \
v0 -= (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (SUM - 0x9E3779B9U + K1)
DSTEP(0xC6EF3720U, k2, k3);
DSTEP(0x28B7BD67U, k3, k2);
DSTEP(0x8A8043AEU, k0, k1);
DSTEP(0xEC48C9F5U, k1, k0);
DSTEP(0x4E11503CU, k2, k3);
DSTEP(0xAFD9D683U, k2, k2);
DSTEP(0x11A25CCAU, k3, k1);
DSTEP(0x736AE311U, k0, k0);
DSTEP(0xD5336958U, k1, k3);
DSTEP(0x36FBEF9FU, k1, k2);
DSTEP(0x98C475E6U, k2, k1);
DSTEP(0xFA8CFC2DU, k3, k0);
DSTEP(0x5C558274U, k0, k3);
DSTEP(0xBE1E08BBU, k1, k2);
DSTEP(0x1FE68F02U, k1, k1);
DSTEP(0x81AF1549U, k2, k0);
DSTEP(0xE3779B90U, k3, k3);
DSTEP(0x454021D7U, k0, k2);
DSTEP(0xA708A81EU, k1, k1);
DSTEP(0x08D12E65U, k1, k0);
DSTEP(0x6A99B4ACU, k2, k3);
DSTEP(0xCC623AF3U, k3, k2);
DSTEP(0x2E2AC13AU, k0, k1);
DSTEP(0x8FF34781U, k0, k0);
DSTEP(0xF1BBCDC8U, k1, k3);
DSTEP(0x5384540FU, k2, k2);
DSTEP(0xB54CDA56U, k3, k1);
DSTEP(0x1715609DU, k0, k0);
DSTEP(0x78DDE6E4U, k0, k3);
DSTEP(0xDAA66D2BU, k1, k2);
DSTEP(0x3C6EF372U, k2, k1);
DSTEP(0x9E3779B9U, k3, k0);
#endif
if (iv) {
v0 ^= AV_RB32(iv);
v1 ^= AV_RB32(iv + 4);
memcpy(iv, src, 8);
}
} else {
#if CONFIG_SMALL
int i;
uint32_t sum = 0, delta = 0x9E3779B9U;
for (i = 0; i < 32; i++) {
v0 += (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + ctx->key[sum & 3]);
sum += delta;
v1 += (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + ctx->key[(sum >> 11) & 3]);
}
#else
#define ESTEP(SUM, K0, K1) \
v0 += (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (SUM + K0);\
v1 += (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (SUM + 0x9E3779B9U + K1)
ESTEP(0x00000000U, k0, k3);
ESTEP(0x9E3779B9U, k1, k2);
ESTEP(0x3C6EF372U, k2, k1);
ESTEP(0xDAA66D2BU, k3, k0);
ESTEP(0x78DDE6E4U, k0, k0);
ESTEP(0x1715609DU, k1, k3);
ESTEP(0xB54CDA56U, k2, k2);
ESTEP(0x5384540FU, k3, k1);
ESTEP(0xF1BBCDC8U, k0, k0);
ESTEP(0x8FF34781U, k1, k0);
ESTEP(0x2E2AC13AU, k2, k3);
ESTEP(0xCC623AF3U, k3, k2);
ESTEP(0x6A99B4ACU, k0, k1);
ESTEP(0x08D12E65U, k1, k1);
ESTEP(0xA708A81EU, k2, k0);
ESTEP(0x454021D7U, k3, k3);
ESTEP(0xE3779B90U, k0, k2);
ESTEP(0x81AF1549U, k1, k1);
ESTEP(0x1FE68F02U, k2, k1);
ESTEP(0xBE1E08BBU, k3, k0);
ESTEP(0x5C558274U, k0, k3);
ESTEP(0xFA8CFC2DU, k1, k2);
ESTEP(0x98C475E6U, k2, k1);
ESTEP(0x36FBEF9FU, k3, k1);
ESTEP(0xD5336958U, k0, k0);
ESTEP(0x736AE311U, k1, k3);
ESTEP(0x11A25CCAU, k2, k2);
ESTEP(0xAFD9D683U, k3, k2);
ESTEP(0x4E11503CU, k0, k1);
ESTEP(0xEC48C9F5U, k1, k0);
ESTEP(0x8A8043AEU, k2, k3);
ESTEP(0x28B7BD67U, k3, k2);
#endif
}
AV_WB32(dst, v0);
AV_WB32(dst + 4, v1);
}
void av_xtea_crypt(AVXTEA *ctx, uint8_t *dst, const uint8_t *src, int count,
uint8_t *iv, int decrypt)
{
int i;
if (decrypt) {
while (count--) {
xtea_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];
xtea_crypt_ecb(ctx, dst, dst, decrypt, NULL);
memcpy(iv, dst, 8);
} else {
xtea_crypt_ecb(ctx, dst, src, decrypt, NULL);
}
src += 8;
dst += 8;
}
}
}
#ifdef TEST
#include <stdio.h>
#define XTEA_NUM_TESTS 6
static const uint8_t xtea_test_key[XTEA_NUM_TESTS][16] = {
{ 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f },
{ 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f },
{ 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f },
{ 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, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }
};
static const uint8_t xtea_test_pt[XTEA_NUM_TESTS][8] = {
{ 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48 },
{ 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
{ 0x5a, 0x5b, 0x6e, 0x27, 0x89, 0x48, 0xd7, 0x7f },
{ 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48 },
{ 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
{ 0x70, 0xe1, 0x22, 0x5d, 0x6e, 0x4e, 0x76, 0x55 }
};
static const uint8_t xtea_test_ct[XTEA_NUM_TESTS][8] = {
{ 0x49, 0x7d, 0xf3, 0xd0, 0x72, 0x61, 0x2c, 0xb5 },
{ 0xe7, 0x8f, 0x2d, 0x13, 0x74, 0x43, 0x41, 0xd8 },
{ 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
{ 0xa0, 0x39, 0x05, 0x89, 0xf8, 0xb8, 0xef, 0xa5 },
{ 0xed, 0x23, 0x37, 0x5a, 0x82, 0x1a, 0x8c, 0x2d },
{ 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 }
};
static void test_xtea(AVXTEA *ctx, uint8_t *dst, const uint8_t *src,
const uint8_t *ref, int len, uint8_t *iv, int dir,
const char *test)
{
av_xtea_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)
{
AVXTEA ctx;
uint8_t buf[8], iv[8];
int i;
static const uint8_t src[32] = "HelloWorldHelloWorldHelloWorld";
uint8_t ct[32];
uint8_t pl[32];
for (i = 0; i < XTEA_NUM_TESTS; i++) {
av_xtea_init(&ctx, xtea_test_key[i]);
test_xtea(&ctx, buf, xtea_test_pt[i], xtea_test_ct[i], 1, NULL, 0, "encryption");
test_xtea(&ctx, buf, xtea_test_ct[i], xtea_test_pt[i], 1, NULL, 1, "decryption");
/* encrypt */
memcpy(iv, "HALLO123", 8);
av_xtea_crypt(&ctx, ct, src, 4, iv, 0);
/* decrypt into pl */
memcpy(iv, "HALLO123", 8);
test_xtea(&ctx, pl, ct, src, 4, iv, 1, "CBC decryption");
memcpy(iv, "HALLO123", 8);
test_xtea(&ctx, ct, ct, src, 4, iv, 1, "CBC inplace decryption");
}
printf("Test encryption/decryption success.\n");
return 0;
}
#endif
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