Re: [PROPOSAL/PATCH] Fortuna PRNG in /dev/random

Theodore Ts'o
2004-09-28T00:08:25Z

On Mon, Sep 27, 2004 at 03:45:02PM -0400, Jean-Luc Cooke wrote:
> > Actually trying to replace the partial MD4 might be worth an attempt:
> > I'm certain that the partial MD4 is not the best/fastest way to generate
> > sequence numbers.
>
> It infact uses two full SHA1 hashs for tcp sequence numbers (endian and
> padding issues aside). my patch aims to do this in 1 AES256 Encrypt or 2
> AES256 encrypts for ipv6.

No, that's not correct. We rekey once at most every five minutes, and
that requires a SHA hash, but in the normal case, it's only a partial MD4.

An AES encrypt for every TCP connection *might* be faster, but I'd
want to time it to make sure, and doing a bulk test ala "openssl
speed" isn't necessarily going to be predictive, as I've discussed earlier.

- Ted