Re: On the Security of Short Authentication Strings

[Cullen Jennings <fluffy@xxxxxxxxx>]

On Mar 18, 2007, at 9:44 AM, Werner Dittmann wrote:

> EKR wrote:
> > Two basic mechanisms have been proposed for providing
> > authentication for media-plane key management for RTPSEC:
> >
> >   1. Cryptographically bind the MPKM to the signalling.
>
> With the current protocol (SIP) and the usage of this protocol
> this is very hard, if at all, to achive are cryptographically
> strong (or even good) binding. While RFC4474 may be ok for
> identity, it fails for cryptographically strong binding of
> keying material.

Could you elaborate on what the problem is here or what you mean by a  
cryptographically strong binding?