Secure Outsourced Attribute-Based Signatures
Attribute-Based Signature (ABS) is a useful variant of digital signature, which enables users to sign messages over attributes without revealing any information other than the fact that they have attested to the messages. However, heavy computational cost is required during signing in existing work of ABS, which grows linearly with the size of the predicate formula. As a result, this presents a significant challenge for resource-limited users (such as mobile devices) to perform such heavy computation independently. Aiming at tackling the challenge above, the authors propose and formalize a new paradigm called OABS, in which the computational overhead at user side is greatly reduced through outsourcing such intensive computation to an untrusted Signing-Cloud Service Provider (S-CSP).