Re: Fwd: Re: IKEv2 Key Size Conformance Requirements

[Dan McDonald <danmcd@east.sun.com>]

> All of us know that 1024 bits key makes 128 - 8 bit bytes, since the
> computer industry is shifting more and more to embedded cryptography, i.e
> in the VLSI chips. I believe we should keep the pattern of integral
> multiples of bytes. In other words we keep the 1024 bits keys.

I strongly disagree.  The _implementation_ of a 1023-bit key will be padded
to the logical 8-bit boundary, of course.  When _generating_ a prime, that
prime may not always have the most-significant bit set out of the, say, 1024
bits possible.  That prime then becomes a 1023-bit prime.

Many device drivers roll-over-and-die because of this, and that's just a bug.
Align things to 1024 for the hardware, but don't limit the user because it
adds a few bits to a device driver.

I have not yet seen a compelling performance case for not handling small
aberrations in size in the device driver.  I will gladly accept real-world
data that indicates accepting 1023 or 1022 bit primes will slow down
performance to an unacceptable level.

Dan