On the Black-Box Separation Between Ring Signatures and Public Key Encryptions

Kyosuke Yamashita; Keisuke Hara

Paper 2023/1319

On the Black-Box Separation Between Ring Signatures and Public Key Encryptions

Kyosuke Yamashita

, Osaka University

Keisuke Hara, National Institute of Advanced Industrial Science and Technology

Abstract

In this paper, we show that it is impossible to construct a public key encryption scheme (PKE) from a ring signature scheme in a black-box fashion in the standard model. Such an impossibility is highly non-trivial because, to the best of our knowledge, known generic constructions of ring signature scheme are based on public key cryptosystems or in the random oracle model. Technically, we introduce a new cryptographic primitive named indistinguishable multi-designated verifiers signature (IMDVS), and prove that (i) IMDVS is equivalent to PKE, and (ii) it is impossible to construct IMDVS from a ring signature scheme in a generic way. Our result suggests an essential gap between ring signature and group signature, as it is known that group signature implies PKE.

Metadata

Available format(s): PDF
Category: Foundations
Publication info: Preprint.
Keywords: black-box separation ring signature public key encryption
Contact author(s): yamashita @ ist osaka-u ac jp
hara-keisuke @ aist go jp
History: 2023-09-08: approved; 2023-09-05: received; See all versions
Short URL: https://ia.cr/2023/1319
License: CC BY-SA

BibTeX

@misc{cryptoeprint:2023/1319,
      author = {Kyosuke Yamashita and Keisuke Hara},
      title = {On the Black-Box Separation Between Ring Signatures and Public Key Encryptions},
      howpublished = {Cryptology {ePrint} Archive, Paper 2023/1319},
      year = {2023},
      url = {https://eprint.iacr.org/2023/1319}
}