New Extensions of Pairing-Based Signatures into Universal Designated Verifier Signatures.

The concept of universal designated verifier signatures was introduced by Steinfeld, Bull, Wang and Pieprzyk at Asiacrypt 2003. We propose two new efficient constructions for pairing-based short signatures. The first scheme is based on Boneh-Boyen signatures and, its security can be analyzed in the standard security model. We reduce its resistance to forgery to the hardness of the strong Diffie-Hellman problem, under the knowledge-of-exponent assumption. The second scheme is compatible with the Boneh-Lynn-Shacham signatures and is proven unforgeable, in the random oracle model, under the assumption that the computational bilinear Diffie-Hellman problem is untractable. Both schemes are designed for devices with constrained computation capabilities since the signing and the designation procedure are pairing-free. [ABSTRACT FROM AUTHOR]