A Universal Designated Verifier Signature Scheme with Non-Delegatability in the Standard Model

In a designated verifier signature (DVS) scheme a signer creates a signature which is only verifiable by a designated verifier. A DVS is a useful scheme for authenticating a signer without disturbing her privacy. In a universal DVS (UDVS) scheme, everyone who holds Alice’s traditional signature on a message (the signature holder), is able to transform it to a DVS for a specific verifier. Non-delegatability is a critical property of a DVS scheme in applications where the responsibility of a signer is important and cannot be delegated to another entity. In this paper, we will propose a non-delegatable UDVS scheme and prove its security requirements in the standard model (without random oracles). To the best of our knowledge, our scheme is the first non-delegatable UDVS scheme and also by considering the signer herself as the signature holder, our scheme is also the first non-delegatable DVS scheme in the standard model.