Leakage-free ID-Based Signature, Revisited

A novel ID-based proxy-protected signature scheme based on identity information is presented in this paper. We review the concept ID-Based signature introduced by Shamir, define the security notion of an ID-Based signature. We also improve the Shamir’s ID-Based signature and prove its security under the proposed security notion. From the improved Shamir’s ID-Based signature scheme we construct an ID-Based proxy signature scheme, the security is based on the underlying ID-based signature scheme. Our scheme is efficient and easy to implement. The scheme simplifies the public key as the user’s id and can be easily applied to all the RSA-type cryptosystems.

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.

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

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.

In mobile multi-server authentication, a client can access different servers over an insecure channel like Internet and wireless networks for numerous online applications. In the literature, several multi-server authentication schemes for mobile clients have been devised. However, most of them are insecure against ephemeral secret leakage (ESL) attack and other vulnerabilities. For mutual authentication and key agreement, mobile client and server used ephemeral secrets (random numbers) and leakage of these secrets may be possible in practice. Since these are generated by an external source that may be controlled by an adversary. Also they are generally pre-computed and stored in insecure devices. Thus, if the secrets are leaked then the session key would turn out to be known and the private keys of client and server may be compromised from the eavesdropped messages. This phenomenon is called ESL attack. To defeat the weaknesses, in this paper, we design an ESL attack-free identity-based mutual authentication and key agreement scheme for mobile multi-server environment. The proposed scheme is analyzed and proven to be provably secure in the random oracle model under the Computational Diffie---Hellman assumption.

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.

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.

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.

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.

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.

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.

Vehicular ad hoc network (VANET) is a wireless ad hoc network which is created among vehicles, road side units (RSU) and regional trusted authorities. It provides inter-vehicle communications as well as communication between vehicles and RSUs. An authentication framework has been proposed in order to establish secure communication in VANET environment. Privacy of the vehicles has to be ensured in the network, which avoids misuse of private data. Self-generated public key cryptography based pseudo IDs are used instead of original IDs of vehicles for privacy preservation. The proposed scheme uses id-based signature (IBS) and ID-based online/offline signature (IBOOS) scheme for authentication purpose. Communication between vehicles and RSUs are authenticated using IBS scheme and IBOOS scheme authenticates communication between vehicles. By using these schemes, communication among vehicles under different RSUs and RTAs are also authenticated. Security attacks based on authentication like impersonation attack, Sybil attack are also resolved and the malicious nodes are isolated from the network. Vehicle-to-vehicle authentication without RSUs is also carried out by using RSA algorithm. Finally, the performance of the system is compared with recent schemes. Simulation results show that the proposed scheme provides secure communication among vehicles in the network with less communication and computation overhead.

We present a quantumly secure identity-based signature scheme based on the standard short integer solution problem, featuring tight security reductions in the quantum and classic random oracle models. The scheme has short signatures. Each signature contains a single lattice vector plus a single bit. Compared to the existing tightly secure, short lattice identity-based signature schemes by Pan and Wagner (PQCrypto’21), our scheme has a shorter signature size (around 30% shorter), stronger unforgeability, relies on a weaker assumption, and has detailed proof in the quantum random oracle model.

An efficient provably secure identity-based blind signature (IBBS) scheme based on bilinear pairings is proposed. Assuming the intractability of the q-Strong Diffie-Hellman problem, our IBBS is unforgeable under adaptive chosen-message and ID attack. Because of avoiding using the inefficient MapToPoint function, our IBBS can offer advantages in runtime over the schemes available. Based on this ID-based blind signature scheme, we describe the first ID-based threshold blind signature (TBS) and show that it has security properties of unforgeability and robustness.