Paper 2021/1365
Collusion Resistant Revocable Ring Signatures and Group Signatures from Hard Homogeneous Spaces
Yi-Fu Lai and Samuel Dobson
Abstract
Both ring signatures and group signatures are useful privacy tools, allowing signers to hide their identities within a set of other public keys, while allowing their signatures to be validated with respect to the entire set. Group signature schemes and revocable ring signature schemes both provide the additional ability for certain authorized members to revoke the anonymity on a signature and reveal the true signer—allowing management of abuse in the scheme. This work consists of two parts. Firstly, we introduce a stronger security notion—collusion resistance—for revocable ring signatures and show how to derive a group signature scheme from it, which provides a new approach to obtaining group signatures. This improves on the existing weak security model (e.g. with selfless anonymity) which fails to guarantee anonymity of members whose keys are exposed. Our stronger notion requires that the scheme remains secure against full key exposure in the anonymity game, and allows collusion among arbitrary members in the revocability game. Secondly (and more concretely), we construct a practical collusion-resistant revocable ring signature scheme based on hard homogenous spaces (HHS), and thus obtain a group signature scheme based on isogenies. To the best of our knowledge, the schemes given in this work are the first efficient post-quantum (collusion-resistant) revocable ring signature scheme, and the first efficient isogeny-based group signature scheme in the literature.
Note: 20 Oct: Add a comparison table and fix typos in security notions
Metadata
- Available format(s)
- Category
- Public-key cryptography
- Publication info
- Preprint. MINOR revision.
- Keywords
- group signatureisogeny cryptographyring signaturepost-quantum cryptography
- Contact author(s)
-
ylai276 @ aucklanduni ac nz
samuel dobson nz @ gmail com - History
- 2021-10-20: revised
- 2021-10-12: received
- See all versions
- Short URL
- https://ia.cr/2021/1365
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2021/1365, author = {Yi-Fu Lai and Samuel Dobson}, title = {Collusion Resistant Revocable Ring Signatures and Group Signatures from Hard Homogeneous Spaces}, howpublished = {Cryptology {ePrint} Archive, Paper 2021/1365}, year = {2021}, url = {https://eprint.iacr.org/2021/1365} }