Traceable policy-based signatures and instantiation from lattices
Publication Name
Information Sciences
Abstract
Policy-based signatures (PBS) were proposed by Bellare and Fuchsbauer (PKC 2014) to allow an authorized member of an organization to sign a message on behalf of the organization. The user's authorization is determined by a policy managed by the organization's trusted authority, while the signature preserves the privacy of the organization's policy. Signing keys in PBS do not include user identity information and thus can be passed to others, violating the intention of employing PBS to restrict users’ signing capability. In this work, we introduce the notion of traceability for PBS by including user identity in the signing key such that the trusted authority will be able to open a suspicious signature and recover the signer's identity should the needs arise. We provide rigorous definitions and stringent security notions of traceable PBS (TPBS), capturing the properties of PBS suggested by Bellare-Fuchsbauer and resembling the “full traceability” requirement for group signatures put forward by Bellare-Micciancio-Warinschi (Eurocrypt 2003). As a proof of concept, we provide a modular construction of TPBS, based on a signature scheme, an encryption scheme and a zero-knowledge proof system. Furthermore, to demonstrate the feasibility of achieving TPBS from concrete, quantum-resistant assumptions, we give an instantiation based on lattices.
Open Access Status
This publication may be available as open access
Volume
607
First Page
1286
Last Page
1310
Funding Number
MOE2019-T2-2–083
Funding Sponsor
Natural Sciences and Engineering Research Council of Canada