Key-homomorphic signatures: definitions and applications to multiparty signatures and non-interactive zero-knowledge

David Derler, Daniel Slamanig

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Key-homomorphic properties of cryptographic objects, i.e., homomorphisms on their key space, have proven to be useful, both from a theoretical as well as a practical perspective. Important cryptographic objects such as pseudorandom functions or (public key) encryption have been studied previously with respect to key-homomorphisms. Interestingly, however, signature schemes have not been explicitly investigated in this context so far. We close this gap and initiate the study of key-homomorphic signatures, which turns out to be an interesting and versatile concept. In doing so, we firstly propose a definitional framework for key-homomorphic signatures distilling various natural flavours of key-homomorphic properties. Those properties aim to classify existing signature schemes and thus allow to infer general statements about signature schemes from those classes by simply making black-box use of the respective properties. We apply our definitional framework to show elegant and simple compilers from classes of signature schemes admitting different types of key-homomorphisms to a number of other interesting primitives such as ring signature schemes, (universal) designated verifier signature schemes, simulation-sound extractable non-interactive zero-knowledge arguments, and multisignature schemes. Additionally, using the formalisms provided by our framework, we can prove a tight implication from single-user security to key-prefixed multi-user security for a class of schemes admitting a certain key-homomorphism.

Original languageEnglish
Pages (from-to)1373-1413
JournalDesigns, Codes, and Cryptography
Volume87
Issue number6
DOIs
Publication statusPublished - 2019

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Keywords

  • (Universal) designated verifier signatures
  • Key-homomorphic signatures
  • Multi-user signatures
  • Multisignatures
  • Ring signatures
  • Simulation-sound extractable non-interactive zero-knowledge

ASJC Scopus subject areas

  • Computer Science Applications
  • Applied Mathematics

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