[zeugma]

Why would the govt need to sign the public keys? Just publish them on a govt web site - no signing or management needed. Anybody and everybody can have your public key and they can't do anything with it that would allow them to impersonate you. They can send you an encrypted message with it that only you (with your private key) can decrypt but they can't send a message as you or sign a document as you.

You wouldn't necessarily need the government to do it, but to do need a way to validate keys. We already have an existing PKI infrastructure of sorts, though I've never really depended upon it in the public key servers. I have actually used it as a starting point for certain individuals that I wanted to have the public keys of, but given the way the web of trust works, you still have to manually (i.e., verbally) validate fingerprints. I've often thought the notary public system would actually be something that could be efficiently harnessed for this, but again, you run up into computer literacy/security issues.

[Garth Tater]

"You wouldn't necessarily need the government to do it, but to do need a way to validate keys."

If a public key is published on the govt site it's as validated as it needs to be for the purpose of this system. How could publishing a false public key for a person on other than the govt site be misused?

I'd hate to think of the feds trying to manage a system that required them to do anything more complicated than keep a list of citizens' public keys.