We present a computational technique for combatting junk mail, in particular, and controlling access to a shared resource, in general. The main idea is to require a user to compute a moderately hard, but not intractable, function in order to gain access to the resource, thus preventing frivolous use. To this end we suggest several pricing functions, based on, respectively, extracting square roots modulo a prime, the Fiat-Shamir signature scheme, and the Ong-Schnorr-Shamir (cracked) signature scheme. A Preliminary version of this paper was presented at Crypto'92
The computational technique REF for combating junk mail and controlling access to a shared resource has already been explored.
Pricing via processing or combatting junk mail
In 12th Annual International Cryptology Conference
Computer Science