[pkg-gnupg-maint] Bug#848951: Bug#848951: gnupg: Utilize multiple cores on CPU for encryption and decryption (and compression)

[Boyan Penkov]

Hello Werner,

This sounds interesting, and I'd like to test it on my setups, however I
am quite new to gpg.

Is this straighforward?  What changes should I make to gpg.conf to give
this a shot?

Cheers!

On 12/21/2016 03:11 AM, Werner Koch wrote:
> On Wed, 21 Dec 2016 06:57, witold.baryluk at gmail.com said:
>
>> Using cipher and compression algorithms that can utilize multiple cores
> It is not possible to parallelize encryption using the CFB mode as
> required by OpenPGP.  In theory it would be possible to run the hashing
> (which is also run on the plaintext) on a different thread.  However
> that would complicate matters a lot and I doubt that there will be a
> real benefit.
>
> What would really improve throughput is a different encryption mode to
> replace CFB and its SHA-1 based MDC.  My suggestion to the WG is the use
> of OCB which would be a lot faster: On an X220 you get these values
>
>  AES            |  nanosecs/byte   mebibytes/sec   cycles/byte
>         CFB enc |      1.77 ns/B     537.9 MiB/s      4.08 c/B
>         CFB dec |     0.373 ns/B    2557.6 MiB/s     0.858 c/B
>         OCB enc |     0.436 ns/B    2189.4 MiB/s      1.00 c/B
>         OCB dec |     0.452 ns/B    2107.9 MiB/s      1.04 c/B
>
>                 |  nanosecs/byte   mebibytes/sec   cycles/byte
>  SHA1           |      1.88 ns/B     507.7 MiB/s      4.32 c/B
>
> Thus the theoretical speedup would be 
>
>           CFB    SHA1          OCB
>      enc  1.77 + 1.88 = 3.65   0.44   8 times
>      dec  0.37 + 1.88 = 2.25   0.45   5 times
>
>
>
> Shalom-Salam,
>
>    Werner
>

-- 

Boyan Penkov
www.boyanpenkov.com


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