[FFmpeg-devel] libavutil: Added twofish block cipher

supraja reddy supraja0493 at gmail.com
Sun Jan 25 19:42:37 CET 2015


Hello,

I have made all the changes as suggested. If the number of if-else loops in
init() seem to be too many, please let me know I will change it but I have
put them to handle the return values and overflow issues. If there are any
other changes, please let me know.

Thanks,
Supraja

On Sun, Jan 25, 2015 at 2:22 AM, Giorgio Vazzana <mywing81 at gmail.com> wrote:

> 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
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel at ffmpeg.org
> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: tf4.patch
Type: text/x-patch
Size: 22211 bytes
Desc: not available
URL: <https://ffmpeg.org/pipermail/ffmpeg-devel/attachments/20150126/dd59c06d/attachment.bin>


More information about the ffmpeg-devel mailing list