30 April 1998, Micropatent: Cryptosystem employing worst-case difficult-to solve lattice problem (Assignee -- International Business Machines Corporation) Abstract: A cryptosystem and cryptographic method are provided for performing tasks such as encoding/decoding, signing messages, and verifying identity. The system and method employ a problem which is difficult to solve in the worst case. Because of the worst-case nature of the problem employed, a system and method according to the invention has advantageous level of security, In a class of preferred embodiments, the difficult problem is one of the recognized difficult problems associated with the mathematical theory of lattices. These problems include finding short vectors and sets of basis vectors from a lattice. Cryptographic protocols are performed, using these problems. Ex Claim Text: A cryptographic communications system A comprising: a communications channel; means for generating a public key and a corresponding private key based on an instance of a problem, the problem being difficult to solve in the worst case, the instance of the problem being difficult to solve, commensurate with the difficulty of the worst-case solution of the problem; and means for performing a cryptographic communication protocol, employing the public and private keys generated by the means for generating, with another cryptographic communications system B over the communications channel. Patent Number: 5737425 Issue Date: 1998 04 07 Inventor(s): Ajtai, Miklos If you would like to purchase a copy of this patent, please call MicroPatent at 800-648-6787.