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Re: key management
"Paul A. Karger" says:
> The point is that mutual suspicion on a single host is an operating system
> issue - not a cryptographic protocol issue.
That is untrue. If multiple users share the same key, and they have
access to their own keys, they can trivially read each others
traffic. If they don't have access to their own keys, they can still
cause each other significant pain and suffering. Chosen plaintext
attacks that heretofore seemed absurd become trivial. It becomes
neccessary to trust the remote host rather than trusting that the
remote host is in possession of a user based authenticator. Attacks
against other users communications can be attempted based on the fact
that the users share the same SAIDs. There is more. Perhaps a paper on
the subject would be a good idea. In any case, however, forcing
different users to use the same SAID is not acceptable.
Perry
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