[Resource Topic] 2016/498: Towards Tightly Secure Short Signature and IBE

Welcome to the resource topic for 2016/498

Title:
Towards Tightly Secure Short Signature and IBE

Authors: Xavier Boyen, Qinyi Li

Abstract:

Constructing short signatures with tight security from standard assumptions is a long-standing open problem. We present an adaptively secure, short (and stateless) signature scheme, featuring a constant security loss relative to a conservative hardness assumption, Short Integer Solution (SIS), and the security of a concretely instantiated pseudorandom function (PRF). This gives a class of tightly secure short lattice signature schemes whose security is based on SIS and the underlying assumption of the instantiated PRF. Our signature construction further extends to give a class of tightly and adaptively secure ``compact" Identity-Based Encryption (IBE) schemes, reducible with constant security loss from Regev’s vanilla Learning With Errors (LWE) hardness assumption and the security of a concretely instantiated PRF. Our approach is a novel combination of a number of techniques, including Katz and Wang signature, Agrawal et al.\ lattice-based secure IBE, and Boneh et al.\ key-homomorphic encryption. Our results, at the first time, eliminate the dependency between the number of adversary’s queries and the security of short signature/IBE schemes in the context of lattice-based cryptography. They also indicate that tightly secure PRFs (with constant security loss) would imply tightly, adaptively secure short signature and IBE schemes (with constant security loss).

ePrint: https://eprint.iacr.org/2016/498

Talk: https://www.youtube.com/watch?v=rj1QOMbagFw

Slides: https://iacr.org/cryptodb/archive/2016/ASIACRYPT/presentation/27865.pdf

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