SPCABS: Signature-Policy Comparable Attribute-Based Signatures

Abstract

Attribute-based signature is an attractive cryptographic primitive and finds broad applications in many fields. Existing attribute-based signature schemes deal with attributes in the way of “with” or “without,” and there is no attribute-based signature scheme that supports comparing attributes. Using the 0-encoding and 1-encoding, we propose an access structure algorithm and an attribute expansion algorithm, enabling the attribute-based signature scheme to effectively deal with the comparative attributes. Then, we propose a signature-policy comparable attribute-based signature scheme using the proposed expansion algorithms. The proposed scheme is existentially unforgeable under the computational Diffie–Hellman exponent (CDHE) assumption and achieves privacy in the sense of information theory. Theoretical analysis and simulation experiments show that our method is practical and has significant advantages in storage and computation overhead compared with the trivial way. Comparable attribute-based signature dramatically expands the application scenarios of attribute-based signature.