## Cryptology ePrint Archive: Report 2021/970

Short Identity-Based Signatures with Tight Security from Lattices

Jiaxin Pan and Benedikt Wagner

Abstract: We construct a short and adaptively secure identity-based signature scheme tightly based on the well-known Short Integer Solution (SIS) assumption. Although identity-based signature schemes can be tightly constructed from either standard signature schemes against adaptive corruptions in the multi-user setting or a two-level hierarchical identity-based encryption scheme, neither of them is known with short signature size and tight security based on the SIS assumption. Here short'' means the signature size is independent of the message length, which is in contrast to the tree-based (tight) signatures. Our approach consists of two steps: Firstly, we give two generic transformations (one with random oracles and the other without) from non-adaptively secure identity-based signature schemes to adaptively secure ones tightly. Our idea extends the similar transformation for digital signature schemes. Secondly, we construct a non-adaptively secure identity-based signature scheme based on the SIS assumption in the random oracle model.

Category / Keywords: public-key cryptography / Identity-based signatures, tight security, short integer solution assumption, lattices

Original Publication (with minor differences): PQCrypto 2021
DOI:
10.1007/978-3-030-81293-5_19

Date: received 20 Jul 2021, last revised 19 Oct 2021

Contact author: jiaxin pan at ntnu no, udpto at student kit edu

Available format(s): PDF | BibTeX Citation

Short URL: ia.cr/2021/970

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