On Monday 14 January 2013, 12:36:22, Vincent Hanquez wrote:
On Sat, Jan 12, 2013 at 02:12:44PM +0100, Ertugrul Söylemez wrote:
I've spend some good chunk of time adding KATs and tests, documentation, and making sure the performance was ahead of other haskell implementations.
I suggest looking at Daniel Fischer's arithmoi [1] library, which implements very fast Integer operations and should provide most functionality needed. However, beware of timing attacks.
Very cool library and very similar to what crypto-numbers provides albeit less sophisticated.
I see you're doing a lot of x `shiftR` 1 with Integers. That's pretty bad for performance (at least for integer-gmp, might be not for integer-simple or implementations other than GHC [last I looked, JHC didn't have arbitrary precision Integers and used 64-bit ones, so it'd be fast there]).
I wished I knew about it before implementing the same(ish) functions.
One caveat of the library is the dependence on integer-gmp.
It was meant to be fast, so exploiting the internal representation of Integers in some places was the way to go. I intend to make it portable, but so far am too good at procrastinating. (Making it portable without losing too much performance is nontrivial in some places, that contributes.) Getting a request would make it happen sooner.
Also for the particular purpose of generating safe primes I have written a blazingly fast implementation that uses intelligent sieving and finds even large primes (>= 4096 bits) within seconds or minutes. It's on hpaste [2]. I might turn this into a library at some point.
Seconds or minutes ? that's very different :-) But in any case, it would be a nice addition i think.
My safe prime generation function is probably the most naive possible.