| /* |
| * 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); |
| } |