[FFmpeg-devel] libavutil: Added twofish block cipher

Michael Niedermayer michaelni at gmx.at
Thu Jan 15 20:43:24 CET 2015


On Thu, Jan 15, 2015 at 10:21:22PM +0530, supraja reddy wrote:
> Hello,
> 
> I have attached the patch for twofish implementation. Please let me know if
> there are any changes to be made.
> 
> Thank you,
> 
> Supraja

>  Makefile  |    3 
>  twofish.c |  351 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  twofish.h |   70 ++++++++++++
>  3 files changed, 424 insertions(+)
> b2382c15f440967745b06f0243a023647c5c78eb  tf.patch
> From f86554850a8b0be2e32fcd341ca297c7ce73a941 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 | 351 ++++++++++++++++++++++++++++++++++++++++++++++++++++
>  libavutil/twofish.h |  70 +++++++++++
>  3 files changed, 424 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..a66677b
> --- /dev/null
> +++ b/libavutil/twofish.c
> @@ -0,0 +1,351 @@
> +/*
> + * An implementation of the TwoFish algorithm as mentioned in RFC3713
> + * 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)
> +#define sk_inc 0x02020202
> +#define sk_nex 0x01010101
> +
> +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}
> +};
> +
> +struct AVTWOFISH *av_twofish_alloc(void)
> +{
> +    return av_mallocz(sizeof(struct AVTWOFISH));
> +}
> +
> +const int av_twofish_size = sizeof(AVTWOFISH);
> +

> +static uint8_t q(int i, uint8_t a)
> +{
> +    uint8_t aa, bb, b;
> +    aa = a >> 4;
> +    bb = a & 0x0f;
> +    a = aa ^ bb;
> +    b = aa ^ (R4(bb) & 0x0f) ^ ((aa << 3) & 0x0f);
> +    aa = t[i][a] & 0x0f;
> +    bb = t[i][16 + b] & 0x0f;
> +    a = aa ^ bb;
> +    b = aa ^ (R4(bb) & 0x0f) ^ ((aa << 3) & 0x0f);
> +    aa = t[i][32 + a] & 0x0f;
> +    bb = t[i][48 + b] & 0x0f;
> +    return (bb << 4) + aa;
> +}

this could be done as a 512 entry look up table


> +
> +static uint8_t gfMul(uint8_t a, uint8_t b)
> +{
> +    uint8_t r = 0, t;
> +    while (a) {
> +        if (a & 1)
> +            r = r ^ b;
> +        t = b & 0x80;
> +        b = b << 1;
> +        if (t)
> +            b = b ^ 0x4d;
> +        a = a >> 1;
> +    }
> +    return r;
> +}

I see this is only use during init but if it still matters speedwise
and assuming this is a galois field multiplication the it can be
written as

EXP_GF256[LOG_GF256[a] + LOG_GF256[b]]  (for a!=0 && b!=0)


[...]

> +static void twofish_decrypt(AVTWOFISH *cs, uint8_t *dst, const uint8_t *src, uint8_t *iv)
> +{
> +    uint32_t P[4], x[2], 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--) {
> +        t0 = tf_h(P[2], cs->S, cs->ksize);
> +        t1 = tf_h(LR(P[3], 8), cs->S, cs->ksize);
> +        x[0] = P[2];
> +        x[1] = P[3];
> +        P[2] = LR(P[0], 1) ^ (t0 + t1 + cs->K[2 * i+8]);
> +        P[3] = RR(P[1] ^ (t0 + 2 * t1+ cs->K[2 * i+9]), 1);
> +        P[0] = x[0];
> +        P[1] = x[1];
> +    }

the x[] temporary and moves to/from it can be avoided if this is
unrolled by 2 i think


[...]
> +#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] = {

static const


[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

No snowflake in an avalanche ever feels responsible. -- Voltaire
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