An Lwe-Based Key Transfer Protocol with Anonymity

We introduce a new cryptographic protocol based on the wellknown LearningWith Errors (LWE) problem: a group key transfer protocol which achieves anonymity of the members against each others. This issue is almost absent in the key transfer protocols from the literature but we argue it is a practical property. We motivate our construction by a practical need. We use two essential cryptographic primitives built from LWE: LWE Diffie-Hellman key exchange derived from Regev’s work [Regev, O.: On lattices, learning with errors, random linear codes, and cryptography, in: Proc. of the 37th Annual ACM Symposium on Theory of Computing-STOC ’05 (H. N. Gabow and R. Fagin, eds.), Baltimore, MD, USA, 2005, ACM, New York, 2005, pp. 84-93] and a public key cryptosystem secure under the LWE hardness. We provide a security definition for anonymous key transfer protocol and we achieve anonymity against IND-CPA adversaries.