[FFmpeg-devel] Patch for Cast128 algorithm implementation

supraja reddy supraja0493 at gmail.com
Wed Oct 15 22:58:44 CEST 2014


Hello ,

I hadn't rebased my branch . This is after the sync . Apologies for the
error .

Thanks ,

Supraja

On Thu, Oct 16, 2014 at 12:50 AM, supraja reddy <supraja0493 at gmail.com>
wrote:

> I have updated the changes as requested .  Please look into the attached
> patch and let me know if there is anything else you wish me to change.
>
> Thanks ,
>
> Supraja
>
> On Sun, Oct 12, 2014 at 8:38 PM, Giorgio Vazzana <mywing81 at gmail.com>
> wrote:
>
>> 2014-10-12 13:59 GMT+02:00 supraja reddy <supraja0493 at gmail.com>:
>> > Hello ,
>> >
>> > I , Supraja , am interested to work with ffmpeg as a part of OPW
>> internship
>> > . As a part of the qualification task , I have taken up the
>> implementation
>> > of Cast 128 algorithm implementation . I have written the code for the
>> same
>> > and have attached the patch of the same with this mail . It is currently
>> > written for ecb mode . It takes keysizes of 40 , 80 and 128 bits for
>> now .
>> >
>> > Please let me know if there are any further changes or suggestions .
>>
>> Hello,
>>
>> thanks for your patch! Please make sure to run tools/patcheck as
>> Michael suggested and fix the reported problems.
>> Some preliminary comments below, hopefully I'll have more time to
>> test/review the patch in the following days.
>>
>> > From b7aab16b09db2a3ca16144221f1516f7fec8a7a2 Mon Sep 17 00:00:00 2001
>> > From: Myra <supraja0493 at gmail.com>
>>
>> Make sure your name and email address are configured correctly in git.
>>
>> > Date: Sun, 12 Oct 2014 11:39:24 +0530
>> > Subject: [PATCH] Added cast128 algorithm for ecb mode
>> >
>> > Signed-off-by: Myra <supraja0493 at gmail.com>
>> > ---
>> >  libavutil/Makefile |   3 +
>> >  libavutil/cast5.c  | 521
>> +++++++++++++++++++++++++++++++++++++++++++++++++++++
>> >  libavutil/cast5.h  |  37 ++++
>> >  3 files changed, 561 insertions(+)
>> >  create mode 100644 libavutil/cast5.c
>> >  create mode 100644 libavutil/cast5.h
>> >
>> > diff --git a/libavutil/Makefile b/libavutil/Makefile
>> > index 65c6b53..22d345e 100644
>> > --- a/libavutil/Makefile
>> > +++ b/libavutil/Makefile
>> > @@ -15,6 +15,7 @@ HEADERS = adler32.h
>>                    \
>> >            bprint.h
>>   \
>> >            bswap.h
>>  \
>> >            buffer.h
>>   \
>> > +          cast5.c
>>  \
>> >            channel_layout.h
>>   \
>> >            common.h
>>   \
>> >            cpu.h
>>  \
>> > @@ -82,6 +83,7 @@ OBJS = adler32.o
>>                   \
>> >         blowfish.o
>>  \
>> >         bprint.o
>>  \
>> >         buffer.o
>>  \
>>
>> > +       cast5.o
>>  \
>>
>> You need to add one more space after cast5.o to align the '\'.
>>
>> >         channel_layout.o
>>  \
>> >         cpu.o
>>   \
>> >         crc.o
>>   \
>> > @@ -151,6 +153,7 @@ TESTPROGS = adler32
>>                      \
>> >              base64
>>   \
>> >              blowfish
>>   \
>> >              bprint
>>   \
>>
>> > +            cast5
>> \
>>
>> Same here, one more space is needed.
>>
>> >              cpu
>>  \
>> >              crc
>>  \
>> >              des
>>  \
>> > diff --git a/libavutil/cast5.c b/libavutil/cast5.c
>> > new file mode 100644
>> > index 0000000..ca7200c
>> > --- /dev/null
>> > +++ b/libavutil/cast5.c
>> > @@ -0,0 +1,521 @@
>> > +#include "cast5.h"
>> > +#include "common.h"
>> > +#include "intreadwrite.h"
>>
>> > +#include "timer.h"
>>
>> I don't think we need timer.h
>>
>> > +/*
>> > + * An implementation of the CAST128 algorithm
>>
>> Maybe add a note mentioning the RFC2144.
>>
>> > + * Copyright (c) 2014 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
>> > + */
>> > +
>> > +#define IA(x) ((x>>24) & 0xff)
>> > +#define IB(x) ((x>>16) & 0xff)
>> > +#define IC(x) ((x>>8) & 0xff)
>> > +#define ID(x) (x & 0xff)
>>
>> I'd also suggest to add a macro for circular left shift (left
>> rotation) and use it throughout the code:
>>
>> #define LR(x, c) ((x) << (c) | (x) >> (32 - (c)))
>>
>> > +
>> > +typedef struct AVCAST5 {
>> > +    uint32_t Km[17];
>> > +    uint32_t Kr[17];
>> > +    int rounds;
>> > +} AVCAST5;
>> > +
>>
>> > +
>> > +
>> > +static uint32_t func(uint32_t D, uint32_t Km, uint32_t Kr, int rnum)
>> > +{
>> > +    uint32_t I,t,val;
>> > +    switch(rnum%3){
>> > +        case 0:
>> > +            t=(Km-D);
>> > +            I=(t<<Kr)|(t>>(32-Kr));
>> > +            val=((S1[IA(I)]+S2[IB(I)])^S3[IC(I)])-S4[ID(I)];
>> > +            break;
>>
>> You can probably eliminate t, something like:
>>
>> I = LR(Km - D, Kr);
>>
>> > +        case 1:
>> > +            t=Km+D;
>> > +            I=(t<<Kr)|(t>>(32-Kr));
>> > +            val=((S1[IA(I)]^S2[IB(I)])-S3[IC(I)])+S4[ID(I)];
>> > +            break;
>> > +        case 2:
>> > +            t=(Km^D);
>> > +            I=(t<<Kr)|(t>>(32-Kr));
>> > +            val=((S1[IA(I)]-S2[IB(I)])+S3[IC(I)])^S4[ID(I)];
>> > +            break;
>> > +    }
>> > +    return val;
>> > +}
>> > +
>> > +static void GenerateRoundKeys(int rnds,uint32_t* K, uint32_t* q,
>> uint32_t* p)
>>
>> We could call q->x and p->z to use the same names used in the RFC, and
>> define:
>>
>> static void generate_round_keys(int rounds, uint32_t *K, uint32_t
>> x[4], uint32_t z[4])
>>
>> > +{
>>
>> > +
>> p[0]=q[0]^S5[IB(q[3])]^S6[ID(q[3])]^S7[IA(q[3])]^S8[IC(q[3])]^S7[IA(q[2])];
>> > +
>> p[1]=q[2]^S5[IA(p[0])]^S6[IC(p[0])]^S7[IB(p[0])]^S8[ID(p[0])]^S8[IC(q[2])];
>> > +
>> p[2]=q[3]^S5[ID(p[1])]^S6[IC(p[1])]^S7[IB(p[1])]^S8[IA(p[1])]^S5[IB(q[2])];
>> > +
>> p[3]=q[1]^S5[IC(p[2])]^S6[IB(p[2])]^S7[ID(p[2])]^S8[IA(p[2])]^S6[ID(q[2])];
>>
>> The block above computes p[] from (p[],q[]) and will be repeated
>> later, it could be defined as a macro.
>>
>> > +
>> > +
>> K[1]=S5[IA(p[2])]^S6[IB(p[2])]^S7[ID(p[1])]^S8[IC(p[1])]^S5[IC(p[0])];
>> > +
>> K[2]=S5[IC(p[2])]^S6[ID(p[2])]^S7[IB(p[1])]^S8[IA(p[1])]^S6[IC(p[1])];
>> > +
>> K[3]=S5[IA(p[3])]^S6[IB(p[3])]^S7[ID(p[0])]^S8[IC(p[0])]^S7[IB(p[2])];
>> > +
>> K[4]=S5[IC(p[3])]^S6[ID(p[3])]^S7[IB(p[0])]^S8[IA(p[0])]^S8[IA(p[3])];
>> > +
>>
>> > +
>> q[0]=p[2]^S5[IB(p[1])]^S6[ID(p[1])]^S7[IA(p[1])]^S8[IC(p[1])]^S7[IA(p[0])];
>> > +
>> q[1]=p[0]^S5[IA(q[0])]^S6[IC(q[0])]^S7[IB(q[0])]^S8[ID(q[0])]^S8[IC(p[0])];
>> > +
>> q[2]=p[1]^S5[ID(q[1])]^S6[IC(q[1])]^S7[IB(q[1])]^S8[IA(q[1])]^S5[IB(p[0])];
>> > +
>> q[3]=p[3]^S5[IC(q[2])]^S6[IB(q[2])]^S7[ID(q[2])]^S8[IA(q[2])]^S6[ID(p[0])];
>>
>> Same here, the block above computes q[] from (p[],q[]) and will be
>> repeated later, you could define a macro.
>>
>> > +
>> > +
>> K[5]=S5[ID(q[0])]^S6[IC(q[0])]^S7[IA(q[3])]^S8[IB(q[3])]^S5[IA(q[2])];
>> > +
>> K[6]=S5[IB(q[0])]^S6[IA(q[0])]^S7[IC(q[3])]^S8[ID(q[3])]^S6[IB(q[3])];
>> > +
>> K[7]=S5[ID(q[1])]^S6[IC(q[1])]^S7[IA(q[2])]^S8[IB(q[2])]^S7[ID(q[0])];
>> > +
>> K[8]=S5[IB(q[1])]^S6[IA(q[1])]^S7[IC(q[2])]^S8[ID(q[2])]^S8[ID(q[1])];
>> > +
>> > +
>> p[0]=q[0]^S5[IB(q[3])]^S6[ID(q[3])]^S7[IA(q[3])]^S8[IC(q[3])]^S7[IA(q[2])];
>> > +
>> p[1]=q[2]^S5[IA(p[0])]^S6[IC(p[0])]^S7[IB(p[0])]^S8[ID(p[0])]^S8[IC(q[2])];
>> > +
>> p[2]=q[3]^S5[ID(p[1])]^S6[IC(p[1])]^S7[IB(p[1])]^S8[IA(p[1])]^S5[IB(q[2])];
>> > +
>> p[3]=q[1]^S5[IC(p[2])]^S6[IB(p[2])]^S7[ID(p[2])]^S8[IA(p[2])]^S6[ID(q[2])];
>> > +
>> > +
>> K[9]=S5[ID(p[0])]^S6[IC(p[0])]^S7[IA(p[3])]^S8[IB(p[3])]^S5[IB(p[2])];
>> > +
>> K[10]=S5[IB(p[0])]^S6[IA(p[0])]^S7[IC(p[3])]^S8[ID(p[3])]^S6[IA(p[3])];
>> > +
>> K[11]=S5[ID(p[1])]^S6[IC(p[1])]^S7[IA(p[2])]^S8[IB(p[2])]^S7[IC(p[0])];
>> > +
>> K[12]=S5[IB(p[1])]^S6[IA(p[1])]^S7[IC(p[2])]^S8[ID(p[2])]^S8[IC(p[1])];
>> > +
>> > +
>> q[0]=p[2]^S5[IB(p[1])]^S6[ID(p[1])]^S7[IA(p[1])]^S8[IC(p[1])]^S7[IA(p[0])];
>> > +
>> q[1]=p[0]^S5[IA(q[0])]^S6[IC(q[0])]^S7[IB(q[0])]^S8[ID(q[0])]^S8[IC(p[0])];
>> > +
>> q[2]=p[1]^S5[ID(q[1])]^S6[IC(q[1])]^S7[IB(q[1])]^S8[IA(q[1])]^S5[IB(p[0])];
>> > +
>> q[3]=p[3]^S5[IC(q[2])]^S6[IB(q[2])]^S7[ID(q[2])]^S8[IA(q[2])]^S6[ID(p[0])];
>> > +
>> > +    if(rnds==16) {
>> > +
>> K[13]=S5[IA(q[2])]^S6[IB(q[2])]^S7[ID(q[1])]^S8[IC(q[1])]^S5[ID(q[0])];
>> > +
>> K[14]=S5[IC(q[2])]^S6[ID(q[2])]^S7[IB(q[1])]^S8[IA(q[1])]^S6[ID(q[1])];
>> > +
>> K[15]=S5[IA(q[3])]^S6[IB(q[3])]^S7[ID(q[0])]^S8[IC(q[0])]^S7[IA(q[2])];
>> > +
>> K[16]=S5[IC(q[3])]^S6[ID(q[3])]^S7[IB(q[0])]^S8[IA(q[0])]^S8[IB(q[3])];
>> > +    }
>> > +}
>> > +
>> > +int av_cast5_init(AVCAST5* cs, const uint8_t *key, int key_bits)
>> > +{
>> > +    uint8_t newKey[16];
>> > +    int i;
>> > +    uint32_t p[4],q[4];
>>
>> We need:
>>
>> memset(newKey, 0, sizeof(newKey));
>>
>> > +    if(key_bits%8!=0||key_bits<40||key_bits>128)
>>
>> if (key_bits % 8 || key_bits < 40 || key_bits > 128)
>>
>> > +        return -1;
>> > +    memcpy(newKey,key,16*sizeof(key[0]));
>>
>> memcpy(newKey, key, key_bits / 8);
>>
>> > +    if (key_bits!=128) {
>> > +        for(i=15;i>=key_bits/8;i--)
>> > +            newKey[i]=0x00;
>> > +    }
>>
>> This if() is not needed anymore, since we used memset() on newKey.
>>
>> > +    if(key_bits==128){
>> > +        cs->rounds=16;
>> > +    } else {
>> > +        cs->rounds=12;
>> > +    }
>>
>> cs->rounds = key_bits <= 80 ? 12 : 16;
>>
>> > +    for(i=0;i<4;i++)
>> > +        q[i]=AV_RB32(newKey+(4*i));
>> > +    GenerateRoundKeys(cs->rounds,cs->Km,q,p);
>> > +    GenerateRoundKeys(cs->rounds,cs->Kr,q,p);
>> > +    for(i=0;i<cs->rounds;i++)
>> > +        cs->Kr[i]=cs->Kr[i]&0x1f;
>> > +    return 0;
>> > +}
>> > +
>> > +static void encipher(AVCAST5* cs,uint8_t* dst,const uint8_t* src)
>> > +{
>> > +    int i;
>> > +    uint32_t temp,sdst[2];
>> > +    sdst[0]=AV_RB32(src);
>> > +    sdst[1]=AV_RB32(src+4);
>> > +    for(i=1;i<=cs->rounds;i++){
>> > +        temp=sdst[1];
>> > +        sdst[1]=sdst[0]^(func(sdst[1],cs->Km[i],cs->Kr[i],i));
>> > +        sdst[0]=temp;
>> > +    }
>> > +    AV_WB32(dst,sdst[1]);
>> > +    AV_WB32(dst+4,sdst[0]);
>> > +}
>> > +
>> > +static void decipher(AVCAST5* cs,uint8_t* dst,const uint8_t* src)
>> > +{
>> > +    int i;
>> > +    uint32_t temp,sdst[2];
>> > +    sdst[0]=AV_RB32(src);
>> > +    sdst[1]=AV_RB32(src+4);
>> > +    for(i=cs->rounds;i>0;i--){
>> > +        temp=sdst[1];
>> > +        sdst[1]=sdst[0]^(func(sdst[1],cs->Km[i],cs->Kr[i],i));
>> > +        sdst[0]=temp;
>> > +    }
>> > +    AV_WB32(dst,sdst[1]);
>> > +    AV_WB32(dst+4,sdst[0]);
>> > +}
>> > +
>> > +void av_cast5_crypt(AVCAST5* cs, uint8_t* dst, const uint8_t* src, int
>> count, int decrypt)
>> > +{
>> > +    while(count--)
>> > +    {
>> > +        if(decrypt){
>> > +            decipher(cs,dst,src);
>> > +        } else {
>> > +            encipher(cs,dst,src);
>> > +        }
>> > +        src=src+8;
>> > +        dst=dst+8;
>> > +    }
>> > +}
>> > +
>> > +#include<stdio.h>
>> > +#include<stdlib.h>
>> > +#include"log.h"
>>
>> > +#include"lfg.h"
>>
>> Not sure we need lfg.h?
>>
>> > +
>> > +#ifdef TEST
>> > +int main(int argc, char** argv)
>> > +{
>> > +    AVCAST5 cs;
>> > +    uint8_t
>> Key[3][16]={{0x01,0x23,0x45,0x67,0x12,0x34,0x56,0x78,0x23,0x45,0x67,0x89,0x34,0x56,0x78,0x9a},
>> > +        {0x01,0x23,0x45,0x67,0x12,0x34,0x56,0x78,0x23,0x45},
>> > +        {0x01,0x23,0x45,0x67,0x12}};
>> > +    uint8_t rpt[8]={0x01,0x23,0x45,0x67,0x89,0xab,0xcd,0xef};
>> > +    uint8_t rct[3][8]={{0x23,0x8b,0x4f,0xe5,0x84,0x7e,0x44,0xb2},
>> > +        {0xeb,0x6a,0x71,0x1a,0x2c,0x02,0x27,0x1b},
>> > +        {0x7a,0xc8,0x16,0xd1,0x6e,0x9b,0x30,0x2e}};
>> > +    int i,err=0;
>> > +    uint8_t temp[8];
>> > +    av_log_set_level(AV_LOG_DEBUG);
>> > +    av_cast5_init(&cs,Key[0],128);
>> > +    av_cast5_crypt(&cs,temp,rpt,1,0);
>> > +    for(i=0;i<8;i++){
>> > +        if(rct[0][i]!=temp[i]){
>> > +            av_log(NULL,AV_LOG_ERROR,"%d %02x
>> %02x\n",i,rct[0][i],temp[i]);
>> > +            err=1;
>> > +        }
>> > +    }
>> > +    av_cast5_crypt(&cs,temp,rct[0],1,1);
>> > +    for(i=0;i<8;i++){
>> > +        if(rpt[i]!=temp[i]){
>> > +            av_log(NULL,AV_LOG_ERROR,"%d %02x
>> %02x\n",i,rpt[i],temp[i]);
>> > +            err=1;
>> > +        }
>> > +    }
>> > +    av_cast5_init(&cs,Key[1],80);
>> > +    av_cast5_crypt(&cs,temp,rpt,1,0);
>> > +    for(i=0;i<8;i++){
>> > +        if(rct[1][i]!=temp[i]){
>> > +            av_log(NULL,AV_LOG_ERROR,"%d %02x
>> %02x\n",i,rct[1][i],temp[i]);
>> > +            err=1;
>> > +        }
>> > +    }
>> > +    av_cast5_crypt(&cs,temp,rct[1],1,1);
>> > +    for(i=0;i<8;i++){
>> > +        if(rpt[i]!=temp[i]){
>> > +            av_log(NULL,AV_LOG_ERROR,"%d %02x
>> %02x\n",i,rpt[i],temp[i]);
>> > +            err=1;
>> > +        }
>> > +    }
>> > +    av_cast5_init(&cs,Key[2],40);
>> > +    av_cast5_crypt(&cs,temp,rpt,1,0);
>> > +    for(i=0;i<8;i++){
>> > +        if(rct[2][i]!=temp[i]){
>> > +            av_log(NULL,AV_LOG_ERROR,"%d %02x
>> %02x\n",i,rct[2][i],temp[i]);
>> > +            err=1;
>> > +        }
>> > +    }
>> > +    av_cast5_crypt(&cs,temp,rct[2],1,1);
>> > +    for(i=0;i<8;i++){
>> > +        if(rpt[i]!=temp[i]){
>> > +            av_log(NULL,AV_LOG_ERROR,"%d %02x
>> %02x\n",i,rpt[i],temp[i]);
>> > +            err=1;
>> > +        }
>> > +    }
>> > +    return err;
>> > +}
>> > +
>> > +#endif
>> > +
>> > +
>> > +
>> > +
>> > +
>> > +
>> > diff --git a/libavutil/cast5.h b/libavutil/cast5.h
>> > new file mode 100644
>> > index 0000000..d2196b9
>> > --- /dev/null
>> > +++ b/libavutil/cast5.h
>> > @@ -0,0 +1,37 @@
>> > +/*
>> > + * An implementation of the CAST128 algorithm
>> > + * Copyright (c) 2014 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_CAST5_H
>> > +#define AVUTIL_CAST5_H
>> > +
>> > +#include <stdint.h>
>> > +
>> > +#include "attributes.h"
>> > +#include "version.h"
>> > +
>> > +struct AVCAST5;
>> > +
>> > +int av_cast5_init(struct AVCAST5 *a, const uint8_t *key, int key_bits);
>> > +
>> > +void av_cast5_crypt(struct AVCAST5 *a, uint8_t *dst, const uint8_t
>> *src, int count,int decrypt);
>> > +
>> > +
>> > +#endif
>> > --
>> > 1.8.3.2
>> >
>> _______________________________________________
>> ffmpeg-devel mailing list
>> ffmpeg-devel at ffmpeg.org
>> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>>
>
>
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