The PI's primary areas of research interest are interactive proof systems, fault tolerant distributed computation, cryptography. Research is projected in these areas. Interactive proofs, introduced by Goldwasser, Micali and Rackoff, are an extension of the classical NP notion of what can be efficiently verified. Two new ingredients are added: The verifier may be probabilistic and err slightly, and the verifier can interact with the prover. The PI plans to investigate for which class of problems it is sufficient for the prover to be able to solve the problem itself. This problem has direct application to program testing which will be explored. The rapid development of distributed systems raises the natural question of what tasks can be performed by them (especially when faults occur). In the last four years it has been extensively studied, and to a large extent understood, how to perform any probabilistic computation on inputs distributed among processors in a complete network so that no faulty subset of the processors gets any additional information or can disrupt the computation. Cryptography has recently developed from a primarily empirical field of ad-hoc techniques to a formal discipline. This rigor was accompanied by concrete and practical proposals of systems which were shown, under a variety of candidate hard problems from number theory, to comply with the new security standards. At this time in the development of the field two projects should be undertaken: first, the definitions for the different cryptographic tasks must be unified. And second, new hard problems should be found (possibly from coding theory or the geometry of numbers domain) on which to base cryptographic schemes.
