X-ASVP is a proposed anti-spam protocol that includes an algorithm to derive a set of URL's from an e-mail address. The X-ASVP algorithm produces three URL's, the first URL points to a document on a webserver with hostname "x-asvp" in the same domain as the e-mail address. The second URL is on the host "www.x-asvp" in the same top level domain as the e-mail address, and the third is on the "www.x-asvp.info" webserver run by the X-ASVP controlling committee.
The owner of an e-mail address, or the domain ISP, can post what is known as a meta-document at any of the derived URL's. The meta-document can contain any number of entities defined by the protocol, or by extensions to the protocol.
The X-ASVP Committee has proposed using an entity "BULKMAIL" - "UCE" as a distributed Do Not E-mail Registry. A rulemaking by the Federal Trade Commission recognizing this entity as equivalent to opt-out registration in a "National DNE Registry" would instantly make the majority of UCE (Unsolicited Commercial E-mail) illegal under existing provisions of the CAN-SPAM Act of 2003.
One major advantage of X-ASVP is that it would enhance an ISP's standing to pursue spammers, and provide a new toolset to do so, as the webserver run by the ISP will record IP addresses closer to the origin of spam e-mail than the IP currently recorded in the "last Received:" header by the ISP's mail transfer agent (MTA).
Possible uses for X-ASVP meta-documents include: posting of asymmetric encryption public keys, posting tokens that would be returned in an X-ASVP mail header, and pointers to any other URL's the owner wishes.