Path: utzoo!mnetor!uunet!husc6!endor!siraj From: siraj@endor.harvard.edu (Raad Siraj) Newsgroups: sci.crypt Subject: Function needed. Message-ID: <3523@husc6.harvard.edu> Date: 11 Dec 87 21:12:30 GMT Sender: news@husc6.harvard.edu Reply-To: siraj@endor.UUCP (Raad Siraj) Lines: 23 Organization: I need a function that takes in any variable-length message M of m bits, and a secret key K of k bits, and produces a fixed length bit pattern of s bits. Requirements: 1. Given any number of M's and their corresponding s bit patterns, it should be computationally difficult to compute the s bit pattern of any new message. (difficult enough to exhaust $200 before a solution is found) 2. The function should be simple to implement (much simpler and faster than RSA and DES). Note: This function could be called a hashing or compressed encoding function that acts as a trapdoor or one-way function. Any suggestions or pointers? Ra'ad