Pairing-based strong designated verifier proxy signature scheme with low cost

A proxy signature (PS) scheme has crucial benefits to the delegation operations in an organization. To further provide PS schemes with the property of confidentiality, in this paper, we propose a strong designated verifier PS scheme from pairings. The proposed scheme allows an authorized proxy signer to generate a valid PS on behalf of an original signer such that only the intended verifier is capable of validating it. Besides, the designated verifier cannot transfer the proof to convince any third party, which is referred to as non-transferability. Compared with previous works, ours has lower computational costs. Especially, the delegation process of our proposed scheme is pairing free. Moreover, the security requirement of unforgeability against existential forgery under adaptive chosen-message attacks is formally proven in the random oracle model.