Cryptology ePrint Archive: Report 2017/1188

Signature Schemes with a Fuzzy Private Key

Kenta Takahashi and Takahiro Matsuda and Takao Murakami and Goichiro Hanaoka and Masakatsu Nishigaki

Abstract: In this paper, we introduce a new concept of digital signature that we call \emph{fuzzy signature}, which is a signature scheme that uses a noisy string such as biometric data as a private key, but \emph{does not require user-specific auxiliary data} (which is also called a helper string in the context of fuzzy extractors), for generating a signature. Our technical contributions are three-fold: (1) We first give the formal definition of fuzzy signature, together with a formal definition of a \lq\lq setting'' that specifies some necessary information for fuzzy data. (2) We give a generic construction of a fuzzy signature scheme based on a signature scheme that has certain homomorphic properties regarding keys and satisfies a kind of related key attack security with respect to addition, and a new tool that we call \emph{linear sketch}. (3) We specify two concrete settings for fuzzy data, and for each of the settings give a concrete instantiation of these building blocks for our generic construction, leading to two concrete fuzzy signature schemes.

We also discuss how fuzzy signature schemes can be used to realize a biometric-based PKI that uses biometric data itself as a cryptographic key, which we call the \emph{public biometric infrastructure (PBI)}.

Category / Keywords: public-key cryptography / Fuzzy Signature, Public Biometric Infrastructure

Original Publication (with major differences): ACNS 2015 and ACNS 2016

Date: received 7 Dec 2017

Contact author: t-matsuda at aist go jp

Available format(s): PDF | BibTeX Citation

Note: This is the merged full version of the earlier papers that appear in the proceedings of ACNS 2015 and the proceedings of ACNS 2016.

Version: 20171212:142314 (All versions of this report)

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