Paul Wouters wrote: > I can't preload 50 million keys. I cannot build trust relations > with 50 millions domains. Just like we could not preload 50 > million nameserver pointers. That is the essential point of the paper of David Clark: These certificates are principal components of essentially all public key schemes, except those that are so small in scale that the users can communicate their public keys to each other one to one, in an ad hoc way that is mutually trustworthy. A credit card brand (VISA, for example) may manage more than 50 million PIN numbers. But, it uses agents to do so. The security of the system depends on not only (cryptographical) security between the brand holder and agents but also social security of the agents. Though 4 digit PIN or 16 bit message ID of DNS is cryptographically not very secure, it is a cryptographical issue of each hop, having nothing to do with social security between hops, introduction of which is inevitable for large infrastructures. Masataka Ohta _______________________________________________ Ietf@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf