A Novel ID-Based Partial Delegation with Warrant Proxy Signature Scheme

Recently, Tseng et al. proposed a new notion for identity-based signature (IBS) scheme to resist ephemeral secret leakage (ESL) attacks, called leakage-free identity-based signature (leakage-free IBS), and devised the first secure leakage-free IBS scheme. However, they only considered the situation of the leakage of ephemeral secrets used for generating the signatures. Notice that the private key extraction procedure is probabilistic as well in their scheme, that is, there are ephemeral secrets used by the key generation center to generate the signers’ private keys. It is practical to consider that if the adversary comprises these ephemeral secrets, then he can reveal the master key of the system. Therefore, it is desired to introduce a new security notion for the leakage-free IBS schemes to consider the ESL attacks on both private key extraction and signing procedures. In this paper, we present such security notion. Moreover, we propose two IBS schemes that are proved to be secure under the new security notion.

Post-quantum secure identity-based signature achieving forward secrecy

In this paper, we first propose an efficient provably secure identity-based signature (IBS) scheme based on bilinear pairings, then propose an efficient identity-based blind signature (IBBS) scheme based on our IBS scheme. Assuming the intractability of the Computational Diffie-Hellman Problem, our IBS scheme is unforgeable under adaptive chosen-message and ID attack. Efficiency analyses show that our schemes can offer advantages in runtime over the schemes available. Furthermore, we show that, contrary to the authors claimed, Zhang and Kim’s scheme in ACISP 2003 is one-more forgeable, if the ROS-problem is solvable.

This paper proposes a new identity-based signature scheme. The new scheme is proven to be existentially unforgeable against Chosen-Principle and Chosen-Message CP-CM attackers who are the strongest attackers so far defined for identity-based signatures. The security of our scheme relies on the standard Computational Diffie-Hellman CDH assumption. The proof is given in the random oracle model where a hash function is modelled as random oracle. Analysis shows that our scheme is also more efficient than the state of the art in terms of computation and communication. We finally improve the basic scheme by eliminating the single-point problem, allow using as a proxy signature scheme and enable fast verification in multi-user settings. The basic scheme and its extensions show that our proposal is versatile to realise efficient and secure authentication in various scenarios.

Threshold proxy signature is more practical, flexible and secure than traditional proxy signature and multi-proxy signature schemes. However, the majority of existing identity-based threshold proxy signature schemes is still inefficient and impractical. Cloud services allow users to create, store, edit, and read electronic documents on the internet conveniently. While access control mechanisms enable communications between user terminals and the cloud to be executed securely and in a trusted manner. In this paper, we proposed a refined efficient identity-based threshold proxy signature in the cloud environment. Our approach is not only practical but also enjoys fewer rounds of communication and less operation cost in comparison to the existing schemes. In this paper, we have also introduced the implementation of our approach in the cloud environment.

Galindo and Garcia introduced a light-wight identity-based signature (IBS) based on Schnorr signature in AFRICACRYPT 2009. Despite the simple construction and the ef-ficiency of Galindo-Garcia IBS, to the best of our knowledge, their followers do not appear except the IBS scheme by Fukumitsu and Hasegawa in CANDAR'17. Although their IBS achieves the tight security, the efficiency is worse than Galindo-Garcia IBS. Their result suggests that Galindo-Garcia IBS utilizes some special properties of Schnorr signature, and we have to deeply observe the structures of both Galindo-Garcia IBS and Schnorr signature to construct their followers. In this paper, we aim to generalize Galindo-Garcia IBS and to search necessary properties of building cryptographic primitives. As a result, we introduce a generic construction of an IBS from a sigma protocol, and find necessary properties to prove the security of the resulting IBS.

Comment on “An efficient identity-based signature scheme with provable security”

Recently, the notion of the key-insulated public- key system has been suggested to protect the security of users' private keys. A general idea of this system is changing the user's private key along with the time, but the user's public key remains unchanged. In this paper, we propose a new identity (ID)-based key-insulated signature scheme from bilinear pairings. As compared with the recently proposed ID-based key-insulated signature schemes, our proposed scheme has better performance in the batch verifying phase. For security analysis, our scheme is a provably secure key-insulated signature scheme in the random oracle model and under the computational Diffie-Hellman assumption. Meanwhile, to demonstrate the additional advantage of a key-insulated signature, we present a novel application based on the proposed scheme, called full delegation ID-based proxy signature scheme with time restriction. To our best knowledge, no such a proxy signature scheme is proposed until now.

Identity-based proxy signature (IDBPSE) has attracted many researchers and scholars since it can simplify key management procedure of certificate-based public key setting. Recently, some IDBPSE schemes are constructed in the standard model. However, most of them have very loose security reductions. And they cannot resist the attack from the delegator and have low computational efficiency. In this study, a novel and efficient IDBPSE scheme is constructed, and we also prove its security based on the computational Diffie–Hellman assumption. Compared with other existing IDBPSE schemes, our scheme has two main advantages: tight security reduction and more complete security including resisting the delegator attack. And our scheme has more efficient performance including less computational cost and shorter signature size than most of existing similar IDBPSE schemes. What is more, our scheme does not require secure channels to transfer delegation keys, but other identity-based proxy signature schemes need.

Recently, Tsai et al. constructed an efficient identity-based signature (IBS) scheme and claimed that it was strongly unforgeable in the standard model. Unfortunately, we find that their scheme is insecure. By giving concrete attack, we show that their scheme does not meet the requirement of strong unforgeability. Meanwhile, we demonstrate that there are serious flaws in their security proof. The simulator cannot correctly answer the signing query in the security model. Furthermore, we propose an improved strongly unforgeable IBS scheme without random oracles. Compared with other strongly unforgeable IBS schemes in the standard model, our scheme is more efficient in terms of computation cost and signature size.

Identity-based cryptography plays an important role in current electronic applications. Mediated Rivest-Shamir-Adleman (RSA) is a simple method of sharing RSA secret keys between the user and the security mediator (SEM). Any signature operation must involve these two parties. In this paper, we newly propose an identity-based forward secure threshold signature scheme based on mediated RSA. In this scheme, threshold users can combine multiple mediators to generate a valid signature. The public key can be any identity information such as mail address or internet protocol (IP) address. The scheme has forward security because the secret key is useless for the adversary after it is renewed. At last, we give the related analysis.

Proxy multi-signature allows two or more than two original signers delegate their signing capabilities to the same designated proxy signer respectively and then the proxy signer can create a signature on behalf of them. In this paper the proposed proxy signature scheme has the same function as proxy multi-signature scheme, but based on a different mechanism which is introduced into the proxy signature model by Hu et al in 2007 and improved by Tsai et al. The proposed scheme improves the proxy key generation protocol and make it more secure, and at the same time the proposed scheme has the merits of strong proxy signature and its proxy signature key has the forward security like Tasi's.

Authentication and authorization are crucial for ensuring the security of information systems. Role-based access control (RBAC) can act as an efficient method of managing authorization of system resources. In this paper, we apply identity-based signature (IBS) technique to cryptographically provide user authentication and role-based authorization. To achieve this, we first extend the RBAC model to incorporate identity-based cryptography. Our access control architecture is derived from an identity-based signature scheme on bilinear pairings and eliminates the use of digital certificates. In our suggestion, the manager checks the validity of a user's identity and user's activated roles simultaneously by verifying a corresponding signature, thus the user authentication and role-based authorization procedures can be combined into one operation. We also prove the security of the proposed scheme in the random oracle model.

In a proxy signature scheme, a potential signer delegates his signing power to a proxy, who signs a message on behalf of the original signer. The ring signature allows a user from a set of possible signers to convince the verifier that the author of the signature belongs to the set but identity of the author is not disclosed. In some real situations, we must apply them both concurrently. In this paper, we present an efficient ID-based proxy ring signature scheme and discuss its security and efficiency. It plays an important role in some applications.

Identity-based signature (IBS) which is a paradigm built on public key cryptography has played a significant role in light-weight authentication. With the advent of the post quantum era, the lattice has become a main mathematical tool to construct quantum-immune cryptographic schemes. By utilizing an admissible hash function with compatible algorithms and lattice trapdoors as basic building blocks, we propose a new IBS scheme over lattices. The scheme is proved existentially unforgeable against adaptive identity attacks and chosen message attacks in the standard model under inhomogeneous short integer solution assumption via the generalized partitioning proof technique. Moreover, the scheme needs only logarithmic basic matrices as master public key while keeping the same private key size and signature size as those of other standard model lattice-based IBS schemes. This construction is the first adaptive-ID secure standard model IBS scheme over lattice with such space efficiency.