Verifiable outsourced attribute-based signature scheme

Attribute-based signature (ABS) enables a signer to sign messages over attributes without revealing any information about the master key of the system. Generally, the signer needs to execute modular exponentiation and bilinear pairing for many times in most of ABS systems, which is intolerable for resource-limited devices. In this paper, a secure verifiable outsourced attribute- based signature scheme is proposed, where the computational overload of the signer could be delegated to an untrusted signing-cloud service provider (S-CSP). The proposed scheme can greatly reduce computational cost of the signer and check the correctness of the output returned by S-CSP. The experiment shows that the computational cost for the signer is much smaller than that for directly computing the signature, which is applicable for the resource-limited devices to complete the signing of an ABS system.