Re: [Ocaml-lib-devel] Future of ExtLib

[William N. <wne...@cs...>]

On Apr 9, 2004, at 4:24 PM, Brian Hurt wrote:

> I hadn't thought about it much.  Last time I took a spin through the
> crypto libraries, I was more than a little surprised that not one used 
> GMP
> for RSA.  Which I found quite surprising, as I'm willing to bet that 
> GMP
> would give you the best possible RSA performance with the least work 
> from
> the implementor.  IIRC, GMP already has an "exponentiate in a modular
> field" operation, implemented with tuned assembly code.  This is the 
> core
> operation of RSA.

I was a bit surprised by this as well, so I modified cryptokit to use 
GMP, and I also added in a number of additional features, like DSA, 
SHA-{265, 384, 512}, a number of random number and prime generation 
routines, hash chains, etc.  I've been meaning to package it up for 
quite a while now, but I'm an idiot when it comes to things like 
makefiles, and I was barely able to cobble one together for my own 
needs...  And oh yeah... my ocamldoc code is a bit farkled.

Plus there's the whole issue of getting GMP and MLGMP up and running.  
Anyway, if you have a need for this, I'd be happy to sent you what I 
have.

> For symmetric key and hashing, I was thinking of
> rounding up the hand-tunned assembly versions kicking around.  I 
> haven't
> decided what to do with Elliptic curve yet.

As always, the problem with hand tuned assembly is the portability 
issue, that's why I try to stay away from it where I can -- plus, I'm 
not sure you really get significant enough benefits from assembly 
coding the modern symmetric ciphers and hashes.

And I've been meaning to add some EC stuff to cryptokit-gmp for a long 
time.  Laziness, it'll get you every time.

> Thinking about it a second, there's a problem with providing Ocaml
> implementations of various symmetric key crypto systems- most of them
> assume you have access to efficient 32-bit integers.  Which means you
> either use Int32 at a serious performance and memory hit.

Yep.  And this is one of the biggest pains-in-the-ass for me when it 
comes to OCaml (I do crypto research for a living).  There are times I 
would kill for an efficient  word32/64 datatype... Thank goodness we at 
least have string_unsafe_get and set.

William D. Neumann

"Here come the bunnies with the sugar water,
  Do a little dance with the farmer's daughter."

		-- The Halo Benders