~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ SANDY SANDFORT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C'punks, I put together the following proposal to demonstrate a quick and dirty way to implement a pay-to-play remailer system. I don't care much about the details. Change any of them you feel like. My main concern is the basic pre-paid postage system concept. If those of you who are--or plan to be--remailer operators like it, it's yours. No charge. If you don't like it, well, I guess it's back to the old drawing board. S a n d y P.S. I love the name Spoon-E; everyone else will probably hate it. Consider it one of those details that you should feel free to change. * * * THE ELECTRONIC MAIL FORWARDERS GUILD A Proposal In this Proposal, I briefly discuss the elements a mail forwarders guild might include. My main purpose, however, is to outline a low-tech, anonymous postage system that such a guild could deploy today. My proposed system is intended to serve only as a bridge until a more sophisticated, digital postage/money system is available on the Net. MISSION STATEMENT--The purpose of the Electronic Mail Forwarders Guild (EMFG) would be to: 1. Encourage the proliferation and use of privacy oriented electronic mail forwarding sites, 2. Encourage the adoption of privacy oriented electronic mail forwarding standards and protocols, 3. Create and deploy new products and services on existing electronic mail forwarding sites, 4. To provide mutual aid and assistance with regard to technical, legal and other problems, 5. Establish and maintain an anonymous electronic postage system acceptable by all EMFG members. ANONYMOUS ELECTRONIC POSTAGE SYSTEM POSTAGE RATES--The first questions the EMFG will have to decide concern how much the members wished to charge for their services. Such questions would include: Should each forwarding hop cost the same, or should first and/or last hops receive a premium? Should message lengths be limited? Should longer messages cost more than short ones? Should each kilobyte cost the same, or should each successive kilobytes cost less--or more? Will the EMFG support any free forwarding? What net postage-per-service should EMFG member receive? POSTAGE "STAMP" NAME--The basic unit of postage should be given a "brand name." Using a name instead of an amount, permits bulk discounts and allows price adjustments as circumstances warrant. I favor, "Spooner Electronic Postage Unit" or "Spoon-E" for short (pronounced, "spoonie"). Thus, no matter what a Spoon-E costs, it would always take one Spoon-E to go through one forwarder or whatever. SPOON-E STRUCTURE--Spoon-Es are random 12-digit numbers generated by the clients. POSTAGE ISSUER--The EMFG will need someone to issue Spoon-Es. The EMFG could elect any of the following options: Rotate the uncompensated job among its members, Have member bid for the job in exchange for fixed fee or a percentage cut of each Spoon-E issued, Hire a third-party to issue Spoon-Es in exchange for a fixed fee or a cut. PAYMENT AND ISSUANCE MECHANISM--There are various levels of anonymity available to clients. The choice will depend upon the client's degree of paranoia. They all, however, are processed following these steps: 1. Clients randomly generate a series of 12-digit numbers. 2. These random numbers, plus an extra random 12-digit ID number, are encrypted using the Issuer's public key. 3. This encrypted message and payment are sent to the Issuer. 4. After payment has been accepted, the Issuer puts the clients' random numbers into an "Outstanding Spoon-E" database, and lists the corresponding ID numbers on a "Just Issued Spoon-Es" bulletin board. 5. Clients may access the bulletin board to check when their Spoon-Es have been validated for use. The level of anonymity is determined by the clients' method of payment and transmission. Payment via money order is the most anonymous; personal check, the least. (Cash is even more anonymous, but with its own obvious risk.) The least anonymous method of transmitting the client's 12-digit numbers is via direct e-mail. The most anonymous is via an s-mailed floppy. E-mail through a forwarder is somewhere in between. USE OF POSTAGE--The following steps would be performed in order to forward messages through a series of EMFG sites: 1. Clients consult the Issuer bulletin board to verify that their Spoon-Es are valid. 2. Clients write their messages and include the appropriate number of Spoon-Es within each nested and encrypted "envelope" for each forwarding hop they intend to use. 3. Upon receipt, each forwarder strips out the Spoon-Es for that hop. The message is added to a mix file of other messages until a threshold number is reached. 4. When the threshold is reached, the forwarder contacts the Issuer and verifies the validity of the Spoon-Es. Valid Spoon-Es are removed from the "Outstanding Spoon-E" database and the corresponding messages are forwarded out of mix file in random order. The forwarder's account is credited with the appropriate payment. Messages with invalid or missing Spoon-Es go to the bit or into the free service channel if there is one. 5. Step "4" is repeated through each forwarder until the message is delivered to its ultimate destination. The various mix files help defeat traffic analysis and permit the Spoon-Es to be verified before the forwarding service is performed. CONCLUSIONS The existence of a for-profit (or at least self-funding), privacy enhanced, electronic mail forwarding system does not need to await the development of on-line digital money schemes. It can be deployed today, using readily available, low-tech methods. Such a system benefits from economies of scale, and thus argues in favor of the creation of a group of mail forwarders such as the EMFG. Sandy Sandfort 20 November 1994 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~