Re: Reducing AES tables spaces

[Matt Thomas <matt%3am-software.com@localhost>]

On Nov 18, 2008, at 2:05 PM, Arnaud Lacombe wrote:

> Hi Folks,
>
> I've got this patch for quite a time in my tree, I think some might  
> find
> this interesting.
>
> We currently use in `sys/crypto/rijndael' an AES implementation which
> use 10 huges static tables (in fact, 4 + 4 + 2). They are intended to
> fasten the implementation. Each table entry is a circular  
> permutation of
> the same-index entry of another table. The comment on top of explain
> this better:

Here's my AES implementation.  It's small (5K of code and rodata on  
i386)
and quick.  I've been meaning to replace sys/crypto/rijndael with it.
I consider the existing code to be most writeonly code and wanted to
write an implementation I could understand.

http://www.netbsd.org/~matt/aes.pax

Instead of hand tweaking things, I let the compiler decide what to do.
The heart of the algorithm is only 143 lines and half of that is  
comments.