/* * 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 <string.h> #include "config.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); }