RLWE Commitment-Based Linkable Ring Signature Scheme and Its Application in Blockchain

Abstract

Aiming at the problems of large key size and low computation efficiency of linkable ring signature (LRS) schemes from lattice, we construct a LRS scheme based on the RLWE (learning with errors from ring) commitment scheme and further apply the proposed LRS scheme to blockchain to construct an anonymous post-quantum cryptocurrency model. Concretely, we first prove through setting parameters reasonably, we can make a RLWE-based commitment scheme to have homomorphism; Then use the RLWE-based homomorphic commitment scheme, combined with the Σ-protocol and Fiat-Shamir heuristic to construct a LRS scheme; Finally, by combining the proposed LRS scheme with blockchain we present an anonymous post-quantum cryptocurrency model. Analysis shows that compared with the previous LRS schemes, since the proposed LRS scheme is constructed based on the intractability of RLWE problem which can be reduced to SVP (shortest vector problem) on lattice, it can both resist the quantum computer attacks and have smaller key size, signature size and higher computational efficiency. The proposed cryptocurrency model uses the proposed LRS scheme to ensure the sender’s anonymity and the one-time stealth address to guarantee the recipient’s anonymity, which can both protect users’ identities and resist quantum attacks.