libavutil/xtea.c - third_party/ffmpeg - Git at Google

 /*
  * 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));
 }

 void av_xtea_le_init(AVXTEA *ctx, const uint8_t key[16])
 {
     int i;

     for (i = 0; i < 4; i++)
         ctx->key[i] = AV_RL32(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);
 }

 static void xtea_le_crypt_ecb(AVXTEA *ctx, uint8_t *dst, const uint8_t *src,
                               int decrypt, uint8_t *iv)
 {
     uint32_t v0, v1;
     int i;

     v0 = AV_RL32(src);
     v1 = AV_RL32(src + 4);

     if (decrypt) {
         uint32_t delta = 0x9E3779B9, 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]);
         }
         if (iv) {
             v0 ^= AV_RL32(iv);
             v1 ^= AV_RL32(iv + 4);
             memcpy(iv, src, 8);
         }
     } else {
         uint32_t sum = 0, delta = 0x9E3779B9;

         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]);
         }
     }

     AV_WL32(dst, v0);
     AV_WL32(dst + 4, v1);
 }

 static void xtea_crypt(AVXTEA *ctx, uint8_t *dst, const uint8_t *src, int count,
                        uint8_t *iv, int decrypt,
                        void (*crypt)(AVXTEA *, uint8_t *, const uint8_t *, int, uint8_t *))
 {
     int i;

     if (decrypt) {
         while (count--) {
             crypt(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];
                 crypt(ctx, dst, dst, decrypt, NULL);
                 memcpy(iv, dst, 8);
             } else {
                 crypt(ctx, dst, src, decrypt, NULL);
             }
             src   += 8;
             dst   += 8;
         }
     }
 }

 void av_xtea_crypt(AVXTEA *ctx, uint8_t *dst, const uint8_t *src, int count,
                    uint8_t *iv, int decrypt)
 {
     xtea_crypt(ctx, dst, src, count, iv, decrypt, xtea_crypt_ecb);
 }

 void av_xtea_le_crypt(AVXTEA *ctx, uint8_t *dst, const uint8_t *src, int count,
                       uint8_t *iv, int decrypt)
 {
     xtea_crypt(ctx, dst, src, count, iv, decrypt, xtea_le_crypt_ecb);
 }
	/*
	* 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));
	}

	void av_xtea_le_init(AVXTEA *ctx, const uint8_t key[16])
	{
	int i;

	for (i = 0; i < 4; i++)
	ctx->key[i] = AV_RL32(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);
	}

	static void xtea_le_crypt_ecb(AVXTEA ctx, uint8_t dst, const uint8_t *src,
	int decrypt, uint8_t *iv)
	{
	uint32_t v0, v1;
	int i;

	v0 = AV_RL32(src);
	v1 = AV_RL32(src + 4);

	if (decrypt) {
	uint32_t delta = 0x9E3779B9, 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]);
	}
	if (iv) {
	v0 ^= AV_RL32(iv);
	v1 ^= AV_RL32(iv + 4);
	memcpy(iv, src, 8);
	}
	} else {
	uint32_t sum = 0, delta = 0x9E3779B9;

	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]);
	}
	}

	AV_WL32(dst, v0);
	AV_WL32(dst + 4, v1);
	}

	static void xtea_crypt(AVXTEA ctx, uint8_t dst, const uint8_t *src, int count,
	uint8_t *iv, int decrypt,
	void (crypt)(AVXTEA , uint8_t , const uint8_t , int, uint8_t *))
	{
	int i;

	if (decrypt) {
	while (count--) {
	crypt(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];
	crypt(ctx, dst, dst, decrypt, NULL);
	memcpy(iv, dst, 8);
	} else {
	crypt(ctx, dst, src, decrypt, NULL);
	}
	src += 8;
	dst += 8;
	}
	}
	}

	void av_xtea_crypt(AVXTEA ctx, uint8_t dst, const uint8_t *src, int count,
	uint8_t *iv, int decrypt)
	{
	xtea_crypt(ctx, dst, src, count, iv, decrypt, xtea_crypt_ecb);
	}

	void av_xtea_le_crypt(AVXTEA ctx, uint8_t dst, const uint8_t *src, int count,
	uint8_t *iv, int decrypt)
	{
	xtea_crypt(ctx, dst, src, count, iv, decrypt, xtea_le_crypt_ecb);
	}