Re: Generating Keying Material

[Uri Blumenthal <uri@lucent.com>]

David Faucher wrote:
> 
> Section 4.3 of draft-ietf-ipsec-ikev2-03.txt states
> 
>    "Keying material will always be derived as the output of the
>    negotiated prf algorithm. If the amount of keying material is greater
>    than the size of the output of the prf algorithm, we will use the prf
>    iteratively..."
> 
> Rather than having two methods for generating key material (based on the
> size of key material needed vs. the size of the prf output), wouldn't it
> easier to have prf+ generate a pseudo-random stream from which all key
> material is taken?

My understanding of PRF is that it produces a pseudo-random STREAM.
Otherwise it's not a PRF! (:-)

We can talk about it at the meeting, or at CFRG.

> Keeps it simple and straight forward.
 
Strongly agree.