An Oblivious Transfer Protocol with Log-Squared Communication

Abstract. We propose a one-round 1-out-of-n computationally-private information retrieval protocol for -bit strings with low-degree polylogarithmic receivercomputation, linear sender-computation and communication Θ(k · log2 n + · log n), where k is a possibly non-constant security parameter. The new protocol is receiver-private if the underlying length-flexible additively homomorphic public-key cryptosystem is IND-CPA secure. It can be transformed to a one-round computationally receiver-private and information-theoretically sender-private 1out-of-n oblivious-transfer protocol for -bit strings, that has the same asymptotic communication and is private in the standard complexity-theoretic model. Keywords. Computationally-private information retrieval, length-flexible additively homomorphic public-key cryptosystem, oblivious transfer.

• Type: Conference
• Year: 2005
• Where: ISW
• Authors: Helger Lipmaa
• Keywords: -bit Strings, Computationally-private Information Retrieval, Homomorphic Public-key Cryptosystem, ISW 2005