Mail headers

Hugh's comments brought up a idea to me. RFC 822 is the standard for the format of Internet mail messages. Anybody interested in the remailer should eventually read this thing. In it there is already a standard header field "Encrypted." It accepts two optional arguments, a decryption type and an identifier (say, for key lookup). So we have a way of automatically telling encrypted message without doing pattern recognition on the body. I propose a couple more header fields. "Digest" for signed message digests. "Key-Mgmt" for the distribution of new keys and key compromise certificates, i.e. for automatic key distribution. What else do we need to make a fairly automated crypto mail system? Eric