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Re: CRACK



Ari Huttunen writes:
> There's another architectural thing you should consider. What about modifying
> the protocol so that when the server starts believing in the authenticity of the
> client, the server issues the client's public key a certificate? This certificate
> would have a very limited life-time, just enough for the purpose at hand.
> It would be transported to the client in the 'last' message, whatever that is.
> 
> Although this creates more public key operations, the legacy authentication
> functionality could be located on a different physical box than the actual
> security gateway.. This achieves a very similar function to the Kerberos ticket
> granting server, and the certificate is similar to Kerberos tickets. You'd of
> course have to set up the trust relations appropriately.
> 
> There could also exist "one time certificates" that can be used only once
> during their life-time to gain access, similar to one time passwords. Some
> way or another they would be revoked the moment they are used.
> 
> (CPU is basically very cheap. If not this year, then perhaps next..)

We thought about that, but there are already perfectly good protocols
for obtaining certificates (CEP, PKIX, whatever) and these certificates
could be short-lived for exactly this purpose.  On the other hand,
as you point out, this is a more heavyweight mechanism.  Hence
the draft.

brian
briank@network-alchemy.com




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