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 language | English |
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Pages (from-to) | 1373-1413 |
Journal | Designs, Codes and Cryptography |
Volume | 87 |
Issue number | 6 |
DOIs | |
Publication status | Published - 2019 |
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