Paper 2025/788

Identity-Based Ring Signature from Quantum Token

Nabanita Chakraborty, Indian Institute of Technology of Kharagpur
Ratna Dutta, Indian Institute of Technology of Kharagpur
Abstract

An identity-based ring signature (IRS) is an attractive cryptographic primitive having numerous applications including e-cash and e-voting, that enables a user to authenticate sensitive documents on behalf of a ring of user identities chosen by the signer and provides anonymity and unforgeability. We introduce the first quantum-tokenized identity-based ring signature (QTIRS) scheme qtIRS and its variant D-qtIRS with signature delegation assuming the existence of obfuscated membership-checking circuits and a computationally sound non-interactive zero-knowledge (NIZK) proof system. We emphasize that our schemes are dynamic where a user can join or leave the system without disturbing others, allow unrestricted ring size with signature size independent of the ring size and provide security in the standard model. We enhance our security framework by minimizing restrictions for the adversary and allowing a broader domain to forge and introduce the notion of strong existential unforgeability against adaptive-chosen-message-and-identity attack (sEU-ACMI) and strong anonymity (sAnon). Our scheme qtIRS achieves sEU-ACMI and sAnon security while our scheme D-qtIRS attains strong existential unforgeability against adaptive-chosen-message-and-identity attack with signature delegation (sEU-ACMID) and sAnon. Most interestingly, our D-qtIRS features signature delegation and leased key revocation in the IRS setting, enabling a lessor to grant a limited signing authority to a lessee and revoke the delegated authority whenever needed. Additionally, we have shown the existence of obfuscated membership-checking circuits which is of independent interest.

Metadata
Available format(s)
PDF
Category
Public-key cryptography
Publication info
Preprint.
Keywords
Quantum-tokenObfuscationKey-leasingIdentity-based ring signatureNon-interactive zero-knowledge proof
Contact author(s)
nabanita @ kgpian iitkgp ac in
ratna @ maths iitkgp ac in
History
2025-05-04: approved
2025-05-03: received
See all versions
Short URL
https://ia.cr/2025/788
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2025/788,
      author = {Nabanita Chakraborty and Ratna Dutta},
      title = {Identity-Based Ring Signature from Quantum Token},
      howpublished = {Cryptology {ePrint} Archive, Paper 2025/788},
      year = {2025},
      url = {https://eprint.iacr.org/2025/788}
}
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