Compact Multiple Attribute-Based Signatures With Key Aggregation and Its Application

In blockchain-enabled applications, it is difficult to preserve privacy completely because of the openness of each signer’s public key. In this article, an efficient multiattribute-based signature scheme with key aggregation (M-ABS-KA) is presented that supports a flexible threshold predicate. This construction aggregates the public keys and provides a compact signature that is verified as a group, which realizes faster batch verification than confirming them individually. Furthermore, both the multisignature scale and the public key length are independent of the number of signers and attributes in this scheme. To the best of our knowledge, this M-ABS-KA scheme is the first multi-ABS protocol with an aggregated public key and fast batch verification. Based on the hardness of the computational Diffie–Hellman problem, it is formally proven that the proposal achieves unforgeability in the random oracle model and enjoys signer privacy. Additionally, the performance is evaluated in theoretical and experimental analyses with other related ABS schemes, and the results show that it is feasible and efficient in storage, bandwidth, and computational cost. Finally, as an illustrative application, we design a framework of the blockchain-enabled electronic health records assessment system based on this presented M-ABS-KA scheme.