[FFmpeg-devel] libavutil: added camellia block cipher

[supraja reddy]

Hello,

I have updated the patch. Please let me know if any further changes are
required.

Thanks,

Supraja

On Sat, Dec 27, 2014 at 11:04 PM, Giorgio Vazzana <mywing81 at gmail.com>
wrote:

> 2014-12-26 20:01 GMT+01:00 Michael Niedermayer <michaelni at gmx.at>:
> > [...]
> >
> >> +static uint64_t F(uint64_t F_IN, uint64_t KE)
> >> +{
> >> +    uint32_t Zl, Zr;
> >
> >> +    Zl = (F_IN >> 32) ^ (KE >> 32);
> >> +    Zr = (F_IN & MASK32) ^ (KE & MASK32);
> >
> > KE ^= F_IN;
> > Zl = KE >> 32;
> > Zr = KE & MASK32;
> >
> >
> >> +    Zl = ((SBOX1[(Zl >> 24) & MASK8] << 24) | (SBOX2[(Zl >> 16) &
> MASK8] << 16) |(SBOX3[(Zl >> 8) & MASK8] << 8) |(SBOX4[Zl & MASK8]));
> >> +    Zr = ((SBOX2[(Zr >> 24) & MASK8] << 24) | (SBOX3[(Zr >> 16) &
> MASK8] << 16) |(SBOX4[(Zr >> 8) & MASK8] << 8) |(SBOX1[Zr & MASK8]));
> >
> > (Zl >> 24) and (Zr >> 24) are limited to 8bit they should not need
> > & MASK8
> >
> > ((uint32_t)SBOX1[Zl >> 24]) << 24)
>
> Maybe this will be useful later: on 64-bit processors, if MASK8 is a
> 64-bit constant, this may be faster:
>
> KE ^= F_IN;
> Zl = ((uint32_t)SBOX1[KE >> 56] << 24) | ((uint32_t)SBOX2[(KE >> 48) &
> MASK8] << 16) | ...
>
> > +    Zl ^= LR32(Zr, 8);
> > +    Zr ^= LR32(Zl, 16);
> > +    Zl ^= RR32(Zr, 8);
> > +    Zr ^= RR32(Zl, 8);
>
> The instructions above have a long critical path (each one depends on
> the previous one), and this is probably where we lose most speed at
> the moment.
>
> > it would also be possible to reduce the number of operations at the
> > expense of larger tables but iam not sure that would be a good idea
>
> On 64-bit processors, a big speedup can be obtained by computing S and
> P operation together, using 8 8x64 bit sboxes (a total of 16kB of
> data) that can be computed in the initialization phase from
> SBOX1...SBOX4.
>
> But all these suggestions can be implemented later. My main objection
> with this patch is using one big array for all subkeys.
>
> >
> >
> > [...]
> >
> >> +static const int shift1[2][6] = {
> >> +    {0, 15, 30, 17, 17, 17},
> >> +    {0, 15, 15, 15, 34, 17}
> >> +};
> >> +static const int pos1[2][6] = {
> >> +    {0, 4, 10, 16, 18, 22},
> >> +    {2, 6, 8, 14, 20, 24}
> >> +};
> >> +static const int pos2[4][4]= {
> >> +    {0, 12, 16, 22},
> >> +    {6, 14, 24, 28},
> >> +    {2, 10, 20, 32},
> >> +    {4, 8, 18, 26}
> >> +};
> >> +static const int shift2[4][5]= {
> >> +    {0, 45, 15, 17},
> >> +    {15, 30, 32, 17},
> >> +    {0, 30, 30, 51},
> >> +    {15, 15, 30, 34}
> >> +};
> >
> > these could be made uint8_t
> >
> > [...]
> >
> > --
> > Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
> >
> > Frequently ignored answer#1 FFmpeg bugs should be sent to our
> bugtracker. User
> > questions about the command line tools should be sent to the ffmpeg-user
> ML.
> > And questions about how to use libav* should be sent to the libav-user
> ML.
> >
> > _______________________________________________
> > ffmpeg-devel mailing list
> > ffmpeg-devel at ffmpeg.org
> > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> >
> _______________________________________________
> 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: camellia4.patch
Type: text/x-patch
Size: 22253 bytes
Desc: not available
URL: <https://ffmpeg.org/pipermail/ffmpeg-devel/attachments/20141229/f411512c/attachment.bin>