Authors:
Takahiro Matsuda
1
;
Kenta Takahashi
2
and
Goichiro Hanaoka
1
Affiliations:
1
National Institute of Advanced Industrial Science and Technology (AIST), Tokyo and Japan
;
2
Hitachi Ltd., Yokohama and Japan
Keyword(s):
Fuzzy Signature, Linear Sketch, Recovering Attacks.
Related
Ontology
Subjects/Areas/Topics:
Applied Cryptography
;
Biometrics Security and Privacy
;
Cryptographic Techniques and Key Management
;
Data Engineering
;
Databases and Data Security
;
Information and Systems Security
Abstract:
Recently, the notion of fuzzy signature was introduced by Takahashi et al. (ACNS 2015, ACNS 2016, ePrint 2017). It is a signature scheme in which signatures can be generated using “fuzzy data” (i.e. noisy data such as biometric features) as a signing key, without using any additional user-specific data (such as a helper string in the context of fuzzy extractors). One of the main building blocks in the existing fuzzy signature schemes, is a primitive called linear sketch, which can be interpreted as a certain form of (one-way) encoding with which fuzzy data is encoded, and is used in combination with an ordinary signature scheme with certain functional and security properties, to construct a fuzzy signature scheme. Although the security of the underlying linear sketch scheme is very important for the security of the constructed fuzzy signature schemes, a linear sketch scheme is a relatively new primitive, and what security properties its definition and the existing constructions satis
fy, has not been understood well. In order to deepen our understanding of this primitive, in this paper we clarify the security properties achieved by the existing linear sketch schemes. More specifically, we formalize security of a linear sketch scheme against “recovering” attacks, and then clarify that the existing linear sketch schemes achieve sufficiently strong security against them.
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