PKEY CMAC timings

[Richard Levitte]

I think 16k was enough to demonstrate that the timing difference
becomes more marginal the larger the amount of data to encrypt in the
same session is.

This makes me think that we might want to rethink the reset functions,
i.e. the likes of EVP_CIPHER_CTX_reset()...  could we change that
function to become a call down to provider code?  We do allow that for
the non-provider back-ends, they can implement a 'cleanup' function.
Right now, EVP_CIPHER_CTX_reset() just calls the provider's function
to free its operation context, which forces us to re-initialize
everything with a restarted session, i.e. pass the key anew, etc etc
etc.

Cheers,
Richard

On Thu, 18 Jun 2020 06:50:45 +0200,
Hal Murray wrote:
> 
> > How does it look for large input?  As in many kilobytes or megabytes?
> 
> 16K is all I was willing to wait for.  Timing for really long blocks turns 
> into a memory test.  The right unit is ns/byte.  If that's an interesting 
> case, I'll hack some code to do longer blocks.
pp> 
> 1.1.1g
>      AES-128  16 48 16    225   0.225  475ac1c053379e7dbd4ce80b87d2178e
>      AES-128  16 1024 16   1682   1.682  159d6d5c13f35d37c72efc5f6dbf40ad
>      AES-128  16 16384 16  24566  24.566  581f7b133ad6f3697f33c3f836fdb6e6
> 
> 3.0.0 alpha3
>      AES-128  16 48 16    496   0.496  475ac1c053379e7dbd4ce80b87d2178e
>      AES-128  16 1024 16   1953   1.953  159d6d5c13f35d37c72efc5f6dbf40ad
>      AES-128  16 16384 16  24820  24.820  581f7b133ad6f3697f33c3f836fdb6e6
> 
> -----------
> 
> 3.0.0 alpha3:
> CMAC
>      AES-128  16 16384 16  25270  25.270  581f7b133ad6f3697f33c3f836fdb6e6
> PKEY
>      AES-128  16 16384 16  24839  24.839  581f7b133ad6f3697f33c3f836fdb6e6
> EVP_MAC
>      AES-128  16 16384 16  25462  25.462  581f7b133ad6f3697f33c3f836fdb6e6
> EVP_MAC with Preload cipher and key
>      AES-128  16 16384 16  24567  24.567  581f7b133ad6f3697f33c3f836fdb6e6
> 
> 
> 
> -- 
> These are my opinions.  I hate spam.
> 
> 
> 
-- 
Richard Levitte         levitte at openssl.org
OpenSSL Project         http://www.openssl.org/~levitte/