The U.S. government intends to operate a public-key certification system for government users that will also serve the private sector, as well. But a report just completed by Mitre Corp. for the National Institute of Standards and Technology (NIST) puts the price tag at $1 billion for the start-up of the government alone, with a possible $2 billion annual operational cost for managing certificate-revocation lists.
All in all, I'd say this is a pretty good argument for PGP's web of trust model...
Especially given that urban folklore about everyone being only 5 hops away on the network of life. I.e. Everyone is a friend of a friend of a friend of a friend of a friend of anyone else. This was sort of troped upon in "6 degrees of Separation", the John Guare movie/play. If anyone had any concrete data about this, then it might be interesting to calculate the optimum number of people you should get to cosign your public key. Anyone remember enough about Ramsey numbers and Graph Theory? -Peter
Phil