[viff-devel] Multiparty AES in less than 3 seconds per block thanks to Twisted hack

[Ivan Bjerre Damgård]

Hi Marcel,

Very interesting! I think we should discuss this the next SIMAP/CACE  
meeting in Aarhus. We want, of course, that any application runs as  
fast as possible, so we need to think about how we get there in a  
systematic way. For instance, you call what you did a hack - is there  
a more "official" way to do it?

regards, Ivan

Quoting Marcel Keller <mkeller at cs.au.dk>:

> Hi friends of VIFF,
>
> I've now implemented the hack I mentioned at the last SIMAP/CACE  
> meeting. The quintessence of the hack is that we do network  
> communication every time a multiplication or open operation is  
> scheduled, not only after returning the control back to Twisted.
>
> As you can see in the attached graphs, the results are much better  
> and more accurate than without the hack. The graph also shows that  
> inversion by masking still is slower than inversion by  
> exponentiation. However, the gap is smaller because I optimized PRSS  
> which is used more with masking than with exponentiation. I guess  
> that masking is slower because it needs more local computation and  
> the network latency between the test machines is quite low (about  
> 0.1 ms), which increases the impact of local computations.
>
> If you want to try out the hack yourself, you find two patches  
> attached. One is against Twisted 8.2.0 and one against the current  
> tip of my VIFF repository:  
> http://hg.viff.dk/mkeller/rev/d522f9b14b49. The PRSS optimizations  
> can also be found there.
>
> Furthermore, a new version of the document describing the AES  
> implementation is attached. It corrects various errors of the  
> previous version.
>
> Best regards,
> Marcel
>
>
>