Search

Strong designated verifier signature (generally abbreviated to SDVS) allows signers to obtain absolute control over who can verify the signature, while only the designated verifier other than anyone else can verify the validity of a SDVS without being able to transfer the conviction. Certificateless PKC has unique advantages comparing with certificate-based cryptosystems and identity-based PKC, without suffering from key escrow. Motivated by these attractive features, we propose a novel efficient CL-SDVS scheme without bilinear pairings or map-to-point hash operations. The proposed scheme achieves all the required security properties including EUF-CMA, non-transferability, strongness and non-delegatability. We also estimate the computational and communication efficiency. The comparison shows that our scheme outperforms all the previous CL-(S)DVS schemes. Furthermore, the crucial security properties of the CL-SDVS scheme are formally proved based on the intractability of SCDH and ECDL assumptions in random oracle model.

In a strong designated verifier signature with message recovery (SDVSWMR) scheme, only the designated receiver has the capability to recover and validate the message-signature pair. In 2015, using the bilinear pairing, Islam and Biswas presented an SDVSWMR scheme (we call it: IsBi-SDVSWMR) with non-delegatability, which has better performance than other schemes in terms of communication and computation cost. However, in this study, we address that IsBi-SDVSWM scheme does not satisfy the security property of non-delegatability as they claimed and we present two types of delegatability attack to their scheme. We also propose a new and pairing-free SDVSWMR scheme that possesses the following security requirements: non-delegatability, unforgeability, non-transferability and privacy of signer's identity (PrSI). Compared our scheme with other existing related schemes, our scheme obtains better performance; that is, the computational cost is only 58%(lower) of IsBi-SDVSWM scheme (other schemes), and the communication cost is 800 bits that is only 68%(lower) of IsBi-SDVSWM scheme (other schemes). Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A non-delegatable strong designated verifier signature (NSDVS) enforces verification of a signature by a designated verifier only. The concept is useful in various commercial cryptographic applications such as copyright protection, e-voting, and e-libraries. This paper reports the shortest NSDVS so far that consists of only two elements. The scheme is inspired by an identification scheme and Cramer et al.'s OR-proof technique where a prover can prove that he knows at least one out two secrets. It is solidified by a symmetric key based group to group encryption algorithm. Two implementations of the algorithm are reported. The scheme is provably secure with respect to its properties of unforgeability, non-transferability, privacy of signer's identity, and non-delegatability. [ABSTRACT FROM AUTHOR]

Abstract: Non-delegatability is an interesting property of designated verifier signatures (DVS) as it technically makes a signer responsible for the signer’s actions and protects the privacy of the signer. This property is critical for some financial scenarios when a user is required to do something by itself. As more financial applications are running in a mobile and ubiquitous computing environment, an efficient scheme with a non-delegatability property is desirable. This paper proposes such a scheme in an identity-based setting with detailed proofs. Technically, the scheme combines an identity-based Schnorr style signature and an identification method with an OR proof technique gluing the two parts. It is the second scheme secure in a strict model proposed by Huang et al. And it saves about half the communication and computation costs of the first one. [Copyright &y& Elsevier]

Designated verifier signature (DVS) allows a signer to convince a designated verifier that a signature is generated by the signer without letting the verifier transfer the conviction to others, while the public can still tell that the signature must be generated by one of them. Strong DVS (SDVS) strengthens the latter part by restricting the public from telling whether the signature is generated by one of them or by someone else. In this paper, we propose two new SDVS schemes. Compared with existing SDVS schemes, the first new scheme has almost the same signature size and meanwhile, is proven secure in the standard model, while the existing ones are secure in the random oracle model. It has tight security reduction to the DDH assumption and the security of the underlying pseudorandom functions. Our second new scheme is the first SDVS supporting non-delegatability, the notion of which was introduced by Lipmaa, Wang and Bao in the context of DVS in ICALP 2005. The scheme is efficient and is provably secure in the random oracle model based on the discrete logarithm assumption and Gap Diffie-Hellman assumption. [ABSTRACT FROM AUTHOR]

In 2007, Kancharla et al. proposed an identity-based strong designated verifier signature (IBSDVS) scheme based on bilinear pairings, and claimed it unforgeable and non-delegatable. However, in this paper, we show that this scheme is actually delegatable. [ABSTRACT FROM AUTHOR]