Paper 2026/920
CUBE: Partially Blind BBS Signatures for Unlinkable Decentralized Identity
Abstract
Decentralized Identity (DID) systems aim to provide users with self-sovereign control over their credentials. However, verifying identities on public blockchains often risks leaking sensitive attributes and transaction histories, whereas relying on heavy generic cryptographic protocols leads to prohibitive on-chain costs. In this paper, we propose \textbf{CUBE} (Credential Unlinkability using Blinded Elements), a verifiable credential framework that integrates partially blind BBS signatures with Non-Interactive Zero-Knowledge (NIZK) proofs. By shifting complex identity validation off-chain while blinding the core identity-binding elements, the scheme ensures on-chain unlinkability without losing attribute auditability. To prevent Sybil attacks and credential transfer, we integrate a deterministic nullifier tied to Soulbound Tokens (SBTs). We formalize the scheme's system model and establish its security regarding existential unforgeability, signer-blindness, and zero-knowledge. Performance results show that this construction maintains minimal on-chain gas consumption, offering a practical deployment path for privacy-preserving verifiable credentials in Web3 environments.
Metadata
- Available format(s)
-
PDF
- Category
- Applications
- Publication info
- Preprint.
- Keywords
- Decentralized IdentityVerifiable CredentialsZero-Knowledge ProofsBlockchainBlind Signature
- Contact author(s)
- klizz @ ciall0 cn
- History
- 2026-05-14: approved
- 2026-05-10: received
- See all versions
- Short URL
- https://ia.cr/2026/920
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2026/920,
author = {Guohao Lai},
title = {{CUBE}: Partially Blind {BBS} Signatures for Unlinkable Decentralized Identity},
howpublished = {Cryptology {ePrint} Archive, Paper 2026/920},
year = {2026},
url = {https://eprint.iacr.org/2026/920}
}
