Efficient Arguments without Short PCPs

Current constructions of efficient argument systems combine a short (polynomial size) PCP with a cryptographic hashing technique. We suggest an alternative approach for this problem that allows to simplify the underlying PCP machinery using a stronger cryptographic technique. More concretely, we present a direct method for compiling an exponentially long PCP which is succinctly described by a linear oracle function : Fn F into an argument system in which the verifier sends to the prover O(n) encrypted field elements and receives O(1) encryptions in return. This compiler can be based on an arbitrary homomorphic encryption scheme. Applying our general compiler to the exponential size Hadamard code based PCP of Arora et al. (JACM 1998) yields a simple argument system for NP in which the communication from the prover to the verifier only includes a constant number of short encryptions. The main tool we use is a new cryptographic primitive which allows to efficiently commit to a linear fu...

• Type: Conference
• Year: 2007
• Where: COCO
• Authors: Yuval Ishai, Eyal Kushilevitz, Rafail Ostrovsky
• Keywords: Algorithms, COCO 2007, Cryptographic, Cryptographic Hashing Technique, Stronger Cryptographic Technique