[FFmpeg-devel] libavutil: Added twofish block cipher
Giorgio Vazzana
mywing81 at gmail.com
Sat Jan 24 21:52:20 CET 2015
Hello,
thanks for the new patch. As I said the code looks quite good, here's
what I spotted in my review:
> From b46d6a457aeee319fc6e56217a265c9881a34c2c Mon Sep 17 00:00:00 2001
> From: Supraja Meedinti <supraja0493 at gmail.com>
> Date: Thu, 15 Jan 2015 21:35:16 +0530
> Subject: [PATCH] libavutil: Added Twofish block cipher
>
> Signed-off-by: Supraja Meedinti <supraja0493 at gmail.com>
> ---
> libavutil/Makefile | 3 +
> libavutil/twofish.c | 373 ++++++++++++++++++++++++++++++++++++++++++++++++++++
> libavutil/twofish.h | 70 ++++++++++
Missing changelog entry.
> 3 files changed, 446 insertions(+)
> create mode 100644 libavutil/twofish.c
> create mode 100644 libavutil/twofish.h
>
> diff --git a/libavutil/Makefile b/libavutil/Makefile
> index 4db89b8..6caf896 100644
> --- a/libavutil/Makefile
> +++ b/libavutil/Makefile
> @@ -60,6 +60,7 @@ HEADERS = adler32.h \
> time.h \
> timecode.h \
> timestamp.h \
> + twofish.h \
> version.h \
> xtea.h \
>
> @@ -129,6 +130,7 @@ OBJS = adler32.o \
> time.o \
> timecode.o \
> tree.o \
> + twofish.o \
> utils.o \
> xga_font_data.o \
> xtea.o \
> @@ -184,6 +186,7 @@ TESTPROGS = adler32 \
> sha512 \
> softfloat \
> tree \
> + twofish \
> utf8 \
> xtea \
>
> diff --git a/libavutil/twofish.c b/libavutil/twofish.c
> new file mode 100644
> index 0000000..b57a48c
> --- /dev/null
> +++ b/libavutil/twofish.c
> @@ -0,0 +1,373 @@
> +/*
> + * An implementation of the TwoFish algorithm
> + * Copyright (c) 2015 Supraja Meedinti
> + *
> + * 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 "twofish.h"
> +#include "common.h"
> +#include "intreadwrite.h"
> +#include "attributes.h"
> +
> +#define LR(x, n) ((x) << (n) | (x) >> (32 - (n)))
> +#define RR(x, n) ((x) >> (n) | (x) << (32 - (n)))
> +#define R4(x) ((x) >> 1 | (x) << 3)
This macro is never used.
> +#define sk_inc 0x02020202
> +#define sk_nex 0x01010101
I believe these are not needed, see below.
> +
> +typedef struct AVTWOFISH {
> + uint32_t K[40];
> + uint32_t S[4];
> + int ksize;
> +} AVTWOFISH;
> +
> +static const uint8_t MD1[256] = {
> + 0x00, 0x5b, 0xb6, 0xed, 0x05, 0x5e, 0xb3, 0xe8, 0x0a, 0x51, 0xbc, 0xe7, 0x0f, 0x54, 0xb9, 0xe2,
> + 0x14, 0x4f, 0xa2, 0xf9, 0x11, 0x4a, 0xa7, 0xfc, 0x1e, 0x45, 0xa8, 0xf3, 0x1b, 0x40, 0xad, 0xf6,
> + 0x28, 0x73, 0x9e, 0xc5, 0x2d, 0x76, 0x9b, 0xc0, 0x22, 0x79, 0x94, 0xcf, 0x27, 0x7c, 0x91, 0xca,
> + 0x3c, 0x67, 0x8a, 0xd1, 0x39, 0x62, 0x8f, 0xd4, 0x36, 0x6d, 0x80, 0xdb, 0x33, 0x68, 0x85, 0xde,
> + 0x50, 0x0b, 0xe6, 0xbd, 0x55, 0x0e, 0xe3, 0xb8, 0x5a, 0x01, 0xec, 0xb7, 0x5f, 0x04, 0xe9, 0xb2,
> + 0x44, 0x1f, 0xf2, 0xa9, 0x41, 0x1a, 0xf7, 0xac, 0x4e, 0x15, 0xf8, 0xa3, 0x4b, 0x10, 0xfd, 0xa6,
> + 0x78, 0x23, 0xce, 0x95, 0x7d, 0x26, 0xcb, 0x90, 0x72, 0x29, 0xc4, 0x9f, 0x77, 0x2c, 0xc1, 0x9a,
> + 0x6c, 0x37, 0xda, 0x81, 0x69, 0x32, 0xdf, 0x84, 0x66, 0x3d, 0xd0, 0x8b, 0x63, 0x38, 0xd5, 0x8e,
> + 0xa0, 0xfb, 0x16, 0x4d, 0xa5, 0xfe, 0x13, 0x48, 0xaa, 0xf1, 0x1c, 0x47, 0xaf, 0xf4, 0x19, 0x42,
> + 0xb4, 0xef, 0x02, 0x59, 0xb1, 0xea, 0x07, 0x5c, 0xbe, 0xe5, 0x08, 0x53, 0xbb, 0xe0, 0x0d, 0x56,
> + 0x88, 0xd3, 0x3e, 0x65, 0x8d, 0xd6, 0x3b, 0x60, 0x82, 0xd9, 0x34, 0x6f, 0x87, 0xdc, 0x31, 0x6a,
> + 0x9c, 0xc7, 0x2a, 0x71, 0x99, 0xc2, 0x2f, 0x74, 0x96, 0xcd, 0x20, 0x7b, 0x93, 0xc8, 0x25, 0x7e,
> + 0xf0, 0xab, 0x46, 0x1d, 0xf5, 0xae, 0x43, 0x18, 0xfa, 0xa1, 0x4c, 0x17, 0xff, 0xa4, 0x49, 0x12,
> + 0xe4, 0xbf, 0x52, 0x09, 0xe1, 0xba, 0x57, 0x0c, 0xee, 0xb5, 0x58, 0x03, 0xeb, 0xb0, 0x5d, 0x06,
> + 0xd8, 0x83, 0x6e, 0x35, 0xdd, 0x86, 0x6b, 0x30, 0xd2, 0x89, 0x64, 0x3f, 0xd7, 0x8c, 0x61, 0x3a,
> + 0xcc, 0x97, 0x7a, 0x21, 0xc9, 0x92, 0x7f, 0x24, 0xc6, 0x9d, 0x70, 0x2b, 0xc3, 0x98, 0x75, 0x2e
> +};
> +
> +static const uint8_t MD2[256] = {
> + 0x00, 0xef, 0xb7, 0x58, 0x07, 0xe8, 0xb0, 0x5f, 0x0e, 0xe1, 0xb9, 0x56, 0x09, 0xe6, 0xbe, 0x51,
> + 0x1c, 0xf3, 0xab, 0x44, 0x1b, 0xf4, 0xac, 0x43, 0x12, 0xfd, 0xa5, 0x4a, 0x15, 0xfa, 0xa2, 0x4d,
> + 0x38, 0xd7, 0x8f, 0x60, 0x3f, 0xd0, 0x88, 0x67, 0x36, 0xd9, 0x81, 0x6e, 0x31, 0xde, 0x86, 0x69,
> + 0x24, 0xcb, 0x93, 0x7c, 0x23, 0xcc, 0x94, 0x7b, 0x2a, 0xc5, 0x9d, 0x72, 0x2d, 0xc2, 0x9a, 0x75,
> + 0x70, 0x9f, 0xc7, 0x28, 0x77, 0x98, 0xc0, 0x2f, 0x7e, 0x91, 0xc9, 0x26, 0x79, 0x96, 0xce, 0x21,
> + 0x6c, 0x83, 0xdb, 0x34, 0x6b, 0x84, 0xdc, 0x33, 0x62, 0x8d, 0xd5, 0x3a, 0x65, 0x8a, 0xd2, 0x3d,
> + 0x48, 0xa7, 0xff, 0x10, 0x4f, 0xa0, 0xf8, 0x17, 0x46, 0xa9, 0xf1, 0x1e, 0x41, 0xae, 0xf6, 0x19,
> + 0x54, 0xbb, 0xe3, 0x0c, 0x53, 0xbc, 0xe4, 0x0b, 0x5a, 0xb5, 0xed, 0x02, 0x5d, 0xb2, 0xea, 0x05,
> + 0xe0, 0x0f, 0x57, 0xb8, 0xe7, 0x08, 0x50, 0xbf, 0xee, 0x01, 0x59, 0xb6, 0xe9, 0x06, 0x5e, 0xb1,
> + 0xfc, 0x13, 0x4b, 0xa4, 0xfb, 0x14, 0x4c, 0xa3, 0xf2, 0x1d, 0x45, 0xaa, 0xf5, 0x1a, 0x42, 0xad,
> + 0xd8, 0x37, 0x6f, 0x80, 0xdf, 0x30, 0x68, 0x87, 0xd6, 0x39, 0x61, 0x8e, 0xd1, 0x3e, 0x66, 0x89,
> + 0xc4, 0x2b, 0x73, 0x9c, 0xc3, 0x2c, 0x74, 0x9b, 0xca, 0x25, 0x7d, 0x92, 0xcd, 0x22, 0x7a, 0x95,
> + 0x90, 0x7f, 0x27, 0xc8, 0x97, 0x78, 0x20, 0xcf, 0x9e, 0x71, 0x29, 0xc6, 0x99, 0x76, 0x2e, 0xc1,
> + 0x8c, 0x63, 0x3b, 0xd4, 0x8b, 0x64, 0x3c, 0xd3, 0x82, 0x6d, 0x35, 0xda, 0x85, 0x6a, 0x32, 0xdd,
> + 0xa8, 0x47, 0x1f, 0xf0, 0xaf, 0x40, 0x18, 0xf7, 0xa6, 0x49, 0x11, 0xfe, 0xa1, 0x4e, 0x16, 0xf9,
> + 0xb4, 0x5b, 0x03, 0xec, 0xb3, 0x5c, 0x04, 0xeb, 0xba, 0x55, 0x0d, 0xe2, 0xbd, 0x52, 0x0a, 0xe5
> +};
> +
> +static const uint8_t t[2][64] = {
> + {0x08, 0x01, 0x07, 0x0d, 0x06, 0x0f, 0x03, 0x02, 0x00, 0x0b, 0x05, 0x09, 0x0e, 0x0c, 0x0a, 0x04,
> + 0x0e, 0x0c, 0x0b, 0x08, 0x01, 0x02, 0x03, 0x05, 0x0f, 0x04, 0x0a, 0x06, 0x07, 0x00, 0x09, 0x0d,
> + 0x0b, 0x0a, 0x05, 0x0e, 0x06, 0x0d, 0x09, 0x00, 0x0c, 0x08, 0x0f, 0x03, 0x02, 0x04, 0x07, 0x01,
> + 0x0d, 0x07, 0x0f, 0x04, 0x01, 0x02, 0x06, 0x0e, 0x09, 0x0b, 0x03, 0x00, 0x08, 0x05, 0x0c, 0x0a},
> + {0x02, 0x08, 0x0b, 0x0d, 0x0f, 0x07, 0x06, 0x0e, 0x03, 0x01, 0x09, 0x04, 0x00, 0x0a, 0x0c, 0x05,
> + 0x01, 0x0e, 0x02, 0x0b, 0x04, 0x0c, 0x03, 0x07, 0x06, 0x0d, 0x0a, 0x05, 0x0f, 0x09, 0x00, 0x08,
> + 0x04, 0x0c, 0x07, 0x05, 0x01, 0x06, 0x09, 0x0a, 0x00, 0x0e, 0x0d, 0x08, 0x02, 0x0b, 0x03, 0x0f,
> + 0x0b, 0x09, 0x05, 0x01, 0x0c, 0x03, 0x0d, 0x0e, 0x06, 0x04, 0x07, 0x0f, 0x02, 0x00, 0x08, 0x0a}
> +};
t is never used in the code.
> +
> +static const uint8_t q0[256] = {
> + 0xa9, 0x67, 0xb3, 0xe8, 0x04, 0xfd, 0xa3, 0x76, 0x9a, 0x92, 0x80, 0x78, 0xe4, 0xdd, 0xd1, 0x38,
> + 0x0d, 0xc6, 0x35, 0x98, 0x18, 0xf7, 0xec, 0x6c, 0x43, 0x75, 0x37, 0x26, 0xfa, 0x13, 0x94, 0x48,
> + 0xf2, 0xd0, 0x8b, 0x30, 0x84, 0x54, 0xdf, 0x23, 0x19, 0x5b, 0x3d, 0x59, 0xf3, 0xae, 0xa2, 0x82,
> + 0x63, 0x01, 0x83, 0x2e, 0xd9, 0x51, 0x9b, 0x7c, 0xa6, 0xeb, 0xa5, 0xbe, 0x16, 0x0c, 0xe3, 0x61,
> + 0xc0, 0x8c, 0x3a, 0xf5, 0x73, 0x2c, 0x25, 0x0b, 0xbb, 0x4e, 0x89, 0x6b, 0x53, 0x6a, 0xb4, 0xf1,
> + 0xe1, 0xe6, 0xbd, 0x45, 0xe2, 0xf4, 0xb6, 0x66, 0xcc, 0x95, 0x03, 0x56, 0xd4, 0x1c, 0x1e, 0xd7,
> + 0xfb, 0xc3, 0x8e, 0xb5, 0xe9, 0xcf, 0xbf, 0xba, 0xea, 0x77, 0x39, 0xaf, 0x33, 0xc9, 0x62, 0x71,
> + 0x81, 0x79, 0x09, 0xad, 0x24, 0xcd, 0xf9, 0xd8, 0xe5, 0xc5, 0xb9, 0x4d, 0x44, 0x08, 0x86, 0xe7,
> + 0xa1, 0x1d, 0xaa, 0xed, 0x06, 0x70, 0xb2, 0xd2, 0x41, 0x7b, 0xa0, 0x11, 0x31, 0xc2, 0x27, 0x90,
> + 0x20, 0xf6, 0x60, 0xff, 0x96, 0x5c, 0xb1, 0xab, 0x9e, 0x9c, 0x52, 0x1b, 0x5f, 0x93, 0x0a, 0xef,
> + 0x91, 0x85, 0x49, 0xee, 0x2d, 0x4f, 0x8f, 0x3b, 0x47, 0x87, 0x6d, 0x46, 0xd6, 0x3e, 0x69, 0x64,
> + 0x2a, 0xce, 0xcb, 0x2f, 0xfc, 0x97, 0x05, 0x7a, 0xac, 0x7f, 0xd5, 0x1a, 0x4b, 0x0e, 0xa7, 0x5a,
> + 0x28, 0x14, 0x3f, 0x29, 0x88, 0x3c, 0x4c, 0x02, 0xb8, 0xda, 0xb0, 0x17, 0x55, 0x1f, 0x8a, 0x7d,
> + 0x57, 0xc7, 0x8d, 0x74, 0xb7, 0xc4, 0x9f, 0x72, 0x7e, 0x15, 0x22, 0x12, 0x58, 0x07, 0x99, 0x34,
> + 0x6e, 0x50, 0xde, 0x68, 0x65, 0xbc, 0xdb, 0xf8, 0xc8, 0xa8, 0x2b, 0x40, 0xdc, 0xfe, 0x32, 0xa4,
> + 0xca, 0x10, 0x21, 0xf0, 0xd3, 0x5d, 0x0f, 0x00, 0x6f, 0x9d, 0x36, 0x42, 0x4a, 0x5e, 0xc1, 0xe0
> +};
> +
> +static const uint8_t q1[256] = {
> + 0x75, 0xf3, 0xc6, 0xf4, 0xdb, 0x7b, 0xfb, 0xc8, 0x4a, 0xd3, 0xe6, 0x6b, 0x45, 0x7d, 0xe8, 0x4b,
> + 0xd6, 0x32, 0xd8, 0xfd, 0x37, 0x71, 0xf1, 0xe1, 0x30, 0x0f, 0xf8, 0x1b, 0x87, 0xfa, 0x06, 0x3f,
> + 0x5e, 0xba, 0xae, 0x5b, 0x8a, 0x00, 0xbc, 0x9d, 0x6d, 0xc1, 0xb1, 0x0e, 0x80, 0x5d, 0xd2, 0xd5,
> + 0xa0, 0x84, 0x07, 0x14, 0xb5, 0x90, 0x2c, 0xa3, 0xb2, 0x73, 0x4c, 0x54, 0x92, 0x74, 0x36, 0x51,
> + 0x38, 0xb0, 0xbd, 0x5a, 0xfc, 0x60, 0x62, 0x96, 0x6c, 0x42, 0xf7, 0x10, 0x7c, 0x28, 0x27, 0x8c,
> + 0x13, 0x95, 0x9c, 0xc7, 0x24, 0x46, 0x3b, 0x70, 0xca, 0xe3, 0x85, 0xcb, 0x11, 0xd0, 0x93, 0xb8,
> + 0xa6, 0x83, 0x20, 0xff, 0x9f, 0x77, 0xc3, 0xcc, 0x03, 0x6f, 0x08, 0xbf, 0x40, 0xe7, 0x2b, 0xe2,
> + 0x79, 0x0c, 0xaa, 0x82, 0x41, 0x3a, 0xea, 0xb9, 0xe4, 0x9a, 0xa4, 0x97, 0x7e, 0xda, 0x7a, 0x17,
> + 0x66, 0x94, 0xa1, 0x1d, 0x3d, 0xf0, 0xde, 0xb3, 0x0b, 0x72, 0xa7, 0x1c, 0xef, 0xd1, 0x53, 0x3e,
> + 0x8f, 0x33, 0x26, 0x5f, 0xec, 0x76, 0x2a, 0x49, 0x81, 0x88, 0xee, 0x21, 0xc4, 0x1a, 0xeb, 0xd9,
> + 0xc5, 0x39, 0x99, 0xcd, 0xad, 0x31, 0x8b, 0x01, 0x18, 0x23, 0xdd, 0x1f, 0x4e, 0x2d, 0xf9, 0x48,
> + 0x4f, 0xf2, 0x65, 0x8e, 0x78, 0x5c, 0x58, 0x19, 0x8d, 0xe5, 0x98, 0x57, 0x67, 0x7f, 0x05, 0x64,
> + 0xaf, 0x63, 0xb6, 0xfe, 0xf5, 0xb7, 0x3c, 0xa5, 0xce, 0xe9, 0x68, 0x44, 0xe0, 0x4d, 0x43, 0x69,
> + 0x29, 0x2e, 0xac, 0x15, 0x59, 0xa8, 0x0a, 0x9e, 0x6e, 0x47, 0xdf, 0x34, 0x35, 0x6a, 0xcf, 0xdc,
> + 0x22, 0xc9, 0xc0, 0x9b, 0x89, 0xd4, 0xed, 0xab, 0x12, 0xa2, 0x0d, 0x52, 0xbb, 0x02, 0x2f, 0xa9,
> + 0xd7, 0x61, 0x1e, 0xb4, 0x50, 0x04, 0xf6, 0xc2, 0x16, 0x25, 0x86, 0x56, 0x55, 0x09, 0xbe, 0x91
> +};
> +
> +struct AVTWOFISH *av_twofish_alloc(void)
> +{
> + return av_mallocz(sizeof(struct AVTWOFISH));
> +}
> +
> +const int av_twofish_size = sizeof(AVTWOFISH);
> +
> +static uint8_t gfMul(uint8_t a, uint8_t b)
nit: in ffmpeg we prefer gfmul or gf_mul.
> +{
> + uint8_t r = 0, t;
> + while (a) {
Just a note: using while (a || b) might be slightly faster.
> + if (a & 1)
> + r = r ^ b;
> + t = b & 0x80;
> + b = b << 1;
> + if (t)
> + b = b ^ 0x4d;
> + a = a >> 1;
> + }
> + return r;
> +}
> +
> +static uint32_t tf_RS(uint32_t k0, uint32_t k1)
> +{
> + uint8_t s[4], m[8];
> + AV_WL32(m, k0);
> + AV_WL32(m + 4, k1);
> + s[0] = gfMul(0x01, m[0]) ^ gfMul(0xa4, m[1]) ^ gfMul(0x55, m[2]) ^ gfMul(0x87, m[3]) ^ gfMul(0x5a, m[4]) ^ gfMul(0x58, m[5]) ^ gfMul(0xdb, m[6]) ^ gfMul(0x9e, m[7]);
> + s[1] = gfMul(0xa4, m[0]) ^ gfMul(0x56, m[1]) ^ gfMul(0x82, m[2]) ^ gfMul(0xf3, m[3]) ^ gfMul(0x1e, m[4]) ^ gfMul(0xc6, m[5]) ^ gfMul(0x68, m[6]) ^ gfMul(0xe5, m[7]);
> + s[2] = gfMul(0x02, m[0]) ^ gfMul(0xa1, m[1]) ^ gfMul(0xfc, m[2]) ^ gfMul(0xc1, m[3]) ^ gfMul(0x47, m[4]) ^ gfMul(0xae, m[5]) ^ gfMul(0x3d, m[6]) ^ gfMul(0x19, m[7]);
> + s[3] = gfMul(0xa4, m[0]) ^ gfMul(0x55, m[1]) ^ gfMul(0x87, m[2]) ^ gfMul(0x5a, m[3]) ^ gfMul(0x58, m[4]) ^ gfMul(0xdb, m[5]) ^ gfMul(0x9e, m[6]) ^ gfMul(0x03, m[7]);
> + return AV_RL32(s);
> +}
> +
> +static uint32_t tf_h(uint32_t X, uint32_t L[4], int k)
> +{
> + uint8_t y[4], l[4];
> + AV_WL32(y, X);
> + if (k == 4) {
> + AV_WL32(l, L[3]);
> + y[0] = q1[y[0]] ^ l[0];
> + y[1] = q0[y[1]] ^ l[1];
> + y[2] = q0[y[2]] ^ l[2];
> + y[3] = q1[y[3]] ^ l[3];
> + }
> + if (k >= 3) {
> + AV_WL32(l, L[2]);
> + y[0] = q1[y[0]] ^ l[0];
> + y[1] = q1[y[1]] ^ l[1];
> + y[2] = q0[y[2]] ^ l[2];
> + y[3] = q0[y[3]] ^ l[3];
> + }
> + AV_WL32(l, L[1]);
> + y[0] = q1[q0[q0[y[0]] ^ l[0]] ^ (L[0] & 0xff)];
> + y[1] = q0[q0[q1[y[1]] ^ l[1]] ^ ((L[0] >> 8) & 0xff)];
> + y[2] = q1[q1[q0[y[2]] ^ l[2]] ^ ((L[0] >> 16) & 0xff)];
> + y[3] = q0[q1[q1[y[3]] ^ l[3]] ^ (L[0] >> 24)];
> +
> + l[0] = y[0] ^ MD2[y[1]] ^ MD1[y[2]] ^ MD1[y[3]];
> + l[1] = MD1[y[0]] ^ MD2[y[1]] ^ MD2[y[2]] ^ y[3];
> + l[2] = MD2[y[0]] ^ MD1[y[1]] ^ y[2] ^ MD2[y[3]];
> + l[3] = MD2[y[0]] ^ y[1] ^ MD2[y[2]] ^ MD1[y[3]];
> +
> + return AV_RL32(l);
> +}
> +
> +static void twofish_encrypt(AVTWOFISH *cs, uint8_t *dst, const uint8_t *src)
> +{
> + uint32_t P[4], t0, t1;
> + int i;
> + P[0] = AV_RL32(src) ^ cs->K[0];
> + P[1] = AV_RL32(src + 4) ^ cs->K[1];
> + P[2] = AV_RL32(src + 8) ^ cs->K[2];
> + P[3] = AV_RL32(src + 12) ^ cs->K[3];
> + for (i = 0; i < 16; i += 2) {
> + t0 = tf_h(P[0], cs->S, cs->ksize);
> + t1 = tf_h(LR(P[1], 8), cs->S, cs->ksize);
Hmm, we're not using lookup tables from g()... okay for now, but I
fear this will be kind of slow in comparison to other implementations.
We'll have to optimize this once the code has been committed (it's a
matter of adding four 8bit->32bit LUTs as Michael pointed out).
> + P[2] = RR(P[2] ^ (t0 + t1 + cs->K[2 * i + 8]), 1);
> + P[3] = LR(P[3], 1) ^ (t0 + 2 * t1 + cs->K[2 * i + 9]);
> + t0 = tf_h(P[2], cs->S, cs->ksize);
> + t1 = tf_h(LR(P[3], 8), cs->S, cs->ksize);
> + P[0] = RR(P[0] ^ (t0 + t1 + cs->K[2 * i + 10]), 1);
> + P[1] = LR(P[1], 1) ^ (t0 + 2 * t1 + cs->K[2 * i + 11]);
> + }
> + P[2] ^= cs->K[4];
> + P[3] ^= cs->K[5];
> + P[0] ^= cs->K[6];
> + P[1] ^= cs->K[7];
> + AV_WL32(dst, P[2]);
> + AV_WL32(dst + 4, P[3]);
> + AV_WL32(dst + 8, P[0]);
> + AV_WL32(dst + 12, P[1]);
> +}
> +
> +static void twofish_decrypt(AVTWOFISH *cs, uint8_t *dst, const uint8_t *src, uint8_t *iv)
> +{
> + uint32_t P[4], t0, t1;
> + int i;
> + P[2] = AV_RL32(src) ^ cs->K[4];
> + P[3] = AV_RL32(src + 4) ^ cs->K[5];
> + P[0] = AV_RL32(src + 8) ^ cs->K[6];
> + P[1] = AV_RL32(src + 12) ^ cs->K[7];
> + for (i = 15; i >= 0; i -= 2) {
> + t0 = tf_h(P[2], cs->S, cs->ksize);
> + t1 = tf_h(LR(P[3], 8), cs->S, cs->ksize);
> + P[0] = LR(P[0], 1) ^ (t0 + t1 + cs->K[2 * i + 8]);
> + P[1] = RR(P[1] ^ (t0 + 2 * t1 + cs->K[2 * i + 9]), 1);
> + t0 = tf_h(P[0], cs->S, cs->ksize);
> + t1 = tf_h(LR(P[1], 8), cs->S, cs->ksize);
> + P[2] = LR(P[2], 1) ^ (t0 + t1 + cs->K[2 * i + 6]);
> + P[3] = RR(P[3] ^ (t0 + 2 * t1 + cs->K[2 * i + 7]), 1);
> + }
> + P[0] ^= cs->K[0];
> + P[1] ^= cs->K[1];
> + P[2] ^= cs->K[2];
> + P[3] ^= cs->K[3];
> + if (iv) {
> + P[0] ^= AV_RL32(iv);
> + P[1] ^= AV_RL32(iv + 4);
> + P[2] ^= AV_RL32(iv + 8);
> + P[3] ^= AV_RL32(iv + 12);
> + memcpy(iv, src, 16);
> + }
> + AV_WL32(dst, P[2]);
> + AV_WL32(dst + 4, P[3]);
> + AV_WL32(dst + 8, P[0]);
> + AV_WL32(dst + 12, P[1]);
> +}
> +
> +av_cold int av_twofish_init(AVTWOFISH *cs, const uint8_t *Key, int key_bits)
const uint8_t *key (lowercase)
> +{
> + uint32_t key[8], Ke[4], Ko[4], rh, A, B;
Can we call these variables Me, Mo and rho as in the paper?
Also make rho const uint32_t.
> + uint8_t keypad[32];
> + int i, j, k;
> + k = cs->ksize = ((key_bits <=128) ? 128 : ((key_bits <=192) ? 192 : 256)) >> 6;
nit: you could split the previous instruction in two. In "cold"
functions clarity/cleanness is more important I believe.
> + memset(keypad, 0, sizeof(keypad));
> + if (key_bits > 0 && key_bits <= 256)
> + memcpy(keypad, Key, key_bits >> 3);
Maybe return -1 if key_bits < 0, return 0 if key_bits is exactly 128,
192 or 256, and return 1 when the key is padded at the end with
zeroes. In any case, please document this behaviour.
> + for (i = 0; i < 2*k ; i++)
> + key[i] = AV_RL32(keypad + 4 * i);
> + for (i = 0, j = k - 1; j >= 0; i++, j--) {
> + Ke[i] = key[2 * i];
> + Ko[i] = key[2 * i + 1];
> + cs->S[j] = tf_RS(Ke[i], Ko[i]);
> + }
nit: you could simplify these loops a bit if you compute Ke and Ko in
the first one, and only S in the second one.
> + for (i = 0, rh = 0; i < 20; i++, rh += sk_inc ) {
> + A = tf_h(rh, Ke, k);
> + B = tf_h(rh + sk_nex, Ko, k);
> + B = LR(B, 8);
> + cs->K[2 * i] = A + B;
> + cs->K[2 * i + 1] = LR((A + (2 * B)), 9);
> + }
Something like this would be simpler:
for (i = 0; i < 20; i++) {
A = tf_h((2*i )*rho, Me, k);
B = tf_h((2*i+1)*rho, Mo, k);
...
}
> + return 0;
> +}
> +
> +void av_twofish_crypt(AVTWOFISH *cs, uint8_t *dst, const uint8_t *src, int count, uint8_t *iv, int decrypt)
> +{
> + int i;
> + while (count--) {
> + if (decrypt) {
> + twofish_decrypt(cs, dst, src, iv);
> + } else {
> + if (iv) {
> + for (i = 0; i < 16; i++)
> + dst[i] = src[i] ^ iv[i];
> + twofish_encrypt(cs, dst, dst);
> + memcpy(iv, dst, 16);
> + } else {
> + twofish_encrypt(cs, dst, src);
> + }
> + }
> + src = src + 16;
> + dst = dst + 16;
> + }
> +}
> +
> +#ifdef TEST
> +#include<stdio.h>
> +#include<stdlib.h>
> +#include"log.h"
> +
> +int main(int argc, char *argv[])
> +{
> + uint8_t Key[32] = {0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10, 0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff
> + };
> + const uint8_t rct[6][16] = {
> + {0x9f, 0x58, 0x9f, 0x5c, 0xf6, 0x12, 0x2c, 0x32, 0xb6, 0xbf, 0xec, 0x2f, 0x2a, 0xe8, 0xc3, 0x5a},
> + {0xcf, 0xd1, 0xd2, 0xe5, 0xa9, 0xbe, 0x9c, 0xdf, 0x50, 0x1f, 0x13, 0xb8, 0x92, 0xbd, 0x22, 0x48},
> + {0x37, 0x52, 0x7b, 0xe0, 0x05, 0x23, 0x34, 0xb8, 0x9f, 0x0c, 0xfc, 0xca, 0xe8, 0x7c, 0xfa, 0x20},
> + {0x5d, 0x9d, 0x4e, 0xef, 0xfa, 0x91, 0x51, 0x57, 0x55, 0x24, 0xf1, 0x15, 0x81, 0x5a, 0x12, 0xe0},
> + {0xe7, 0x54, 0x49, 0x21, 0x2b, 0xee, 0xf9, 0xf4, 0xa3, 0x90, 0xbd, 0x86, 0x0a, 0x64, 0x09, 0x41},
> + {0x37, 0xfe, 0x26, 0xff, 0x1c, 0xf6, 0x61, 0x75, 0xf5, 0xdd, 0xf4, 0xc3, 0x3b, 0x97, 0xa2, 0x05}
> + };
> + uint8_t temp[32], iv[16], rpt[32] = {0};
> + const int kbits[3] = {128, 192, 256};
> + int i, j, err = 0;
> + AVTWOFISH *cs;
> + cs = av_twofish_alloc();
> + if (!cs)
> + return 1;
> + for (j = 1; j < 3; j++) {
> + av_twofish_init(cs, Key, kbits[j]);
> + av_twofish_crypt(cs, temp, rpt, 1, NULL, 0);
> + for (i = 0; i < 16; i++) {
> + if (rct[j][i] != temp[i]) {
> + av_log(NULL, AV_LOG_ERROR, "%d %02x %02x\n", i, rct[j][i], temp[i]);
> + err = 1;
> + }
> + }
> + av_twofish_crypt(cs, temp, rct[j], 1, NULL, 1);
> + for (i = 0; i < 16; i++) {
> + if (rpt[i] != temp[i]) {
> + av_log(NULL, AV_LOG_ERROR, "%d %02x %02x\n", i, rpt[i], temp[i]);
> + err = 1;
> + }
> + }
> + }
> + for (j = 0; j < 3; j++) {
> + memset(Key, 0, sizeof(Key));
> + memset(rpt, 0, sizeof(rpt));
> + for (i = 1; i < 50; i++) {
> + av_twofish_init(cs, Key, kbits[j]);
> + av_twofish_crypt(cs, temp, rpt, 1, NULL, 0);
> + memcpy(Key+16,Key,(kbits[j]-128) >> 3);
> + memcpy(Key,rpt,16);
> + memcpy(rpt,temp,16);
> + }
> + for (i = 0; i < 16; i++) {
> + if (rct[3 + j][i] != temp[i]) {
> + av_log(NULL, AV_LOG_ERROR, "%d %02x %02x\n", i, rct[3 + j][i], temp[i]);
> + err = 1;
> + }
> + }
> + }
> + memset(rpt, 0, sizeof(rpt));
> + memcpy(iv, "HALLO123HALLO123", 16);
> + av_twofish_crypt(cs, temp, rpt, 2, iv, 0);
> + memcpy(iv, "HALLO123HALLO123", 16);
> + av_twofish_crypt(cs, temp, temp, 2, iv, 1);
> + for (i = 0; i < 32; i++) {
> + if (rpt[i] != temp[i]) {
> + av_log(NULL, AV_LOG_ERROR, "%d %02x %02x\n", i, rpt[i], temp[i]);
> + err = 1;
> + }
> + }
> + av_free(cs);
> + return err;
> +}
> +#endif
> diff --git a/libavutil/twofish.h b/libavutil/twofish.h
> new file mode 100644
> index 0000000..a34b8f6
> --- /dev/null
> +++ b/libavutil/twofish.h
> @@ -0,0 +1,70 @@
> +/*
> + * An implementation of the TwoFish algorithm
> + * Copyright (c) 2015 Supraja Meedinti
> + *
> + * 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_TWOFISH_H
> +#define AVUTIL_TWOFISH_H
> +
> +#include <stdint.h>
> +
> +
> +/**
> + * @file
> + * @brief Public header for libavutil TWOFISH algorithm
> + * @defgroup lavu_twofish TWOFISH
> + * @ingroup lavu_crypto
> + * @{
> + */
> +
> +extern const int av_twofish_size;
> +
> +struct AVTWOFISH;
> +
> +/**
> + * Allocate an AVTWOFISH context
> + * To free the struct: av_free(ptr)
> + */
> +struct AVTWOFISH *av_twofish_alloc(void);
> +
> +/**
> + * Initialize an AVTWOFISH context.
> + *
> + * @param ctx an AVTWOFISH context
> + * @param key a key of 16, 24, 32 bytes used for encryption/decryption
> + * @param key_bits number of keybits: possible are 128, 192, 256
> + */
> +int av_twofish_init(struct AVTWOFISH *ctx, const uint8_t *key, int key_bits);
> +
> +/**
> + * Encrypt or decrypt a buffer using a previously initialized context
> + *
> + * @param ctx an AVTWOFISH context
> + * @param dst destination array, can be equal to src
> + * @param src source array, can be equal to dst
> + * @param count number of 16 byte blocks
> + * @paran iv initialization vector for CBC mode, NULL for ECB mode
> + * @param decrypt 0 for encryption, 1 for decryption
> + */
> +void av_twofish_crypt(struct AVTWOFISH *ctx, uint8_t *dst, const uint8_t *src, int count, uint8_t* iv, int decrypt);
> +
> +/**
> + * @}
> + */
> +#endif /* AVUTIL_TWOFISH_H */
> --
> 1.8.3.2
>
Giorgio Vazzana
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