Re: Question: Key Distr. in realtimeo applications?

How does clipper solve this problem?

It does not. The Clipper initative (FIPS-185) deals solely with the specification of a symmetric cipher with escrowed keys. Key exchange and authentication is outside the scope of the protocol, but most implementations would probably use something like a D-H key exchange to do it (remember that a Clipperphone guarantees privacy between yourself and the person on the other end, but does NOT authenticate them to you or you to them. Man in the middle attacks are obviously possible, depending on the key exchange protocol that your Clipperphones employ.) Ian.