Server-Aided Verification Signatures: Definitions and New Constructions

A server-aided verification signature scheme consists of a standard signature scheme and a server-aided verification protocol. Signatures can be verified by executing the server-aided verification protocol with the server, which is generally untrusted. Therefore, it is suitable for low-power computation devices. In 2011, Wu et al. defined three security notions for server-aided verification signatures, i.e., existential unforgeability, security against collusion attacks and security against strong collusion attacks. In this paper, we propose a new server-aided verification signature, which is provably secure against strong collusion attacks.

One of the most efficient post-quantum signature schemes is Rainbow whose hardness is based on the multivariate quadratic polynomial (MQ) problem. ELSA, a new multivariate signature scheme proposed at Asiacrypt 2017, has a similar construction to Rainbow. Its advantages, compared to Rainbow, are its smaller secret key and faster signature generation. In addition, its existential unforgeability against an adaptive chosen-message attack has been proven under the hardness of the MQ-problem induced by a public key of ELSA with a specific parameter set in the random oracle model. The high efficiency of ELSA is derived from a set of hidden quadratic equations used in the process of signature generation. However, the hidden quadratic equations yield a vulnerability. In fact, a piece of information of these equations can be recovered by using valid signatures and an equivalent secret key can be partially recovered from it. In this paper, we describe how to recover an equivalent secret key of ELSA by a chosen message attack. Our experiments show that we can recover an equivalent secret key for the claimed 128-bit security parameter of ELSA on a standard PC in 177 s with 1326 valid signatures.

Tightly secure signature schemes from the LWE and subset sum assumptions

In recent years, secure communication and privacy‐preserving are gaining popularity because of the advent of wireless network. Certificateless cryptography (CLC) and identity‐based cryptography (IBC) have already been widely applied in the area of wireless network. Hence, to achieve secure communication from CLC to IBC, we present a heterogeneous signcryption scheme that enables a sender in the CLC to transmit a message to multi‐receiver in the IBC. Our scheme has no restrictions on the system parameters and master keys; private key generator and key generating center generate their own system parameters and master key for the IBC users and the CLC user, separately. Considering privacy‐preserving in heterogeneous communication, we show that our scheme can realize the anonymity of all receivers. Compared with other schemes, our scheme has more advantages, such as public verification and decryption fairness, which are attractive for wireless network applications. Moreover, our scheme has the indistinguishability against adaptive chosen ciphertext attacks, the existential unforgeability against adaptive chosen messages attacks, and anonymous indistinguishability of encryptions under selective‐ID, chosen ciphertext attack in the random oracle model. Copyright © 2016 John Wiley & Sons, Ltd.

Vehicular ad hoc networks (VANETs), an application of the Internet of Things (IoT) providing a better intelligent transportation system (ITS), has received substantial attention from both industry and academia. Heterogeneous vehicular communications in VANETs occur when both vehicles and the infrastructure use different cryptographic technologies to exchange safety messages. However, the safety messages between vehicles and the infrastructure are communicated wirelessly; therefore, security issues are a serious concern in this domain. The existing schemes secure the transmission of safety messages with respect to confidentiality, authentication, and nonrepudiation. However, they are inappropriate with respect to efficiency. They cause computational overhead on the receiver and bandwidth overhead in the communications. To cope with this, we propose an elliptic curve cryptosystem-based hybrid signcryption (ECCHSC) protocol that satisfies the security requirements (i.e., message confidentiality, message’s source authentication, message integrity, nonrepudiation, and identity–anonymity) for heterogeneous vehicle-to-infrastructure (V2I) communications in a single logical step. This protocol allows secure transmission of a safety message from a vehicle using identity-based cryptography (IDC) to a roadside unit (RSU) using public-key infrastructure (PKI). In addition, the ECCHSC protocol enables the RSU to receive multiple ciphertexts, aggregate them, and de-signcrypt them simultaneously through the batch de-signcryption method, which further improves the performance. The ECCHSC protocol has indistinguishability against adaptive chosen ciphertext attacks (IND-CCA2) and existential unforgeability against adaptive chosen message attacks (EUF-CMAs) in the random oracle model (ROM). The performance analysis of our protocol demonstrates a significant reduction in computational overhead and in communication/storage overhead as compared to the state-of-the-art schemes.

Authentication is an important aspect for security in any cryptographic application. For Wireless Sensor Networks (WSN), authentication of a message is a vital concern. Authentication is provided through digital signature, and the cost of signing a message is a crucial factor due to the resource constraint nature of a sensor mote. So, there is a need to optimize the cost of computations, involved in the digital signature. In this paper, we present a Pairing-Free Identity Based digital Signature (PF-IBS) algorithm for WSN. PF-IBS is proven secure in terms of existential UnForgeability in the random oracle model against Adaptive Chosen Message Attack (UF-PF-IBS-ACMA). For the performance evaluation of the PF-IBS algorithm, the experimental setup includes MICAz sensor mote with TinyOS and RELIC-Toolkit cryptographic library. The results are gathered with the help of an emulator AVRORA.

To achieve heterogeneous communication from certificateless cryptography (CLC) to identity-based cryptography (IBC), we present a heterogeneous scheme that enables m senders in the CLC to transmit m message to n receivers in the IBC. In the proposed signcryption scheme, each sender is mapped to a distinct pseudo identity, so the sender’s identity privacy preservation can be guaranteed. At the same time, to ensure the receiver’s identity privacy, the identity information of all authorized recipients is mixed by the Lagrange interpolation polynomial during the signcryption process, which prevents the receiver’s identity from being exposed. Compared with existing schemes, the proposed scheme presents efficient computational overhead and is suitable for heterogeneous environments. In addition, our scheme has the indistinguishability against adaptive chosen ciphertext attacks and existential unforgeability against adaptive chosen-message attacks in the random oracle model.

As a variation of ordinary digital signature scheme, a proxy signature scheme enables a proxy signer to sign messages on behalf of the original signer. Proxy multi-signature is an extension of the basic proxy signature primitive, and permits two or more entities to delegate their signing capabilities to some other entity. Many identity-based proxy multi signature (IBPMS) schemes using bilinear pairings have been proposed. But the relative computation cost of the pairing is approximately more than ten times of the scalar multiplication over elliptic curve group. In order to save the running time and the size of the signature, in this paper, we propose an IBPMS scheme without bilinear pairings. We also prove the security of our scheme against adaptive chosen message attack under random oracle model. With the running time being saved greatly, our scheme is more applicable than the previous related schemes for practical applications.KeywordsDigital signatureIdentity-based cryptographyProxy-multi signatureElliptic curve discrete log problem

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

Recently, Boneh and Boyen proposed a new provably secure short signature scheme under the q-strong Diffie-Hellman assumption without random oracles. This scheme is based on bilinear map which is different from Cramer-Shoup signature scheme (which is based on the strong RSA assumption). However, Tan TC[17] showed that Boneh- Boyen scheme is subjected to key substitution attacks in the multi-user setting. In this paper, we propose a new signature scheme. We prove that the proposed scheme is provably secured against existential forgery under adaptive chosen message attack in the standard model and also secure against key substitution attacks.

We describe and analyze a new digital signature scheme. The new scheme is quite efficient, does not require the signer to maintain any state, and can be proven secure against adaptive chosen message attack under a reasonable intractability assumption, the so-called strong RSA assumption. Moreover, a hash function can be incorporated into the scheme in such a way that it is also secure in the random oracle model under the standard RSA assumption.

Unmanned aerial vehicle (UAV) is an attractive application because of its flexibility and economy. It may use a digital signature scheme to protect commands sent to UAVs. Moreover, the digital signature scheme should guarantee the real-time performance of UAVs executing commands and protect the signer’s privacy. Therefore, we proposed an attribute-based proxy signature (ABPS) scheme supporting flexible threshold predicate for UAV networks and proved its security. It has existential unforgeability under selective-predicate and chosen message attacks (EUF-sP-CMA) and can protect the signer’s privacy. We analyzed its computation costs based on experimental data and communication costs. The analysis results indicate that our ABPS scheme has less computation costs than other ABPS schemes and is at the same level as other ABPS schemes on communication costs.

An identity-based multisignature scheme and an identity-based aggregate signature scheme are proposed in this paper. They are both from m-torsion groups on super-singular elliptic curves or hyper-elliptic curves and based on the recently proposed identity-based signature scheme of Cha and Cheon. Due to the sound properties of m-torsion groups and the base scheme, it turns out that our schemes are very simple and efficient. Both schemes are proven to be secure against adaptive chosen message attack in the random oracle model under the normal security notions with the assumption that the Computational Diffie-Hellman problem is hard in the m-torsion groups.

Aggregate signature is widely used in special occasions where the signatures on many different messages generated by many different users need to be compressed into one single signature. This paper presents an efficient certificate-based aggregate signature (CBAS) scheme from bilinear pairing. In the random oracle model, the new scheme is proven existentially unforgeable against adaptive chosen message attacks under the computational Diffie-Hellman assumption. The signature verification of the new scheme only needs constant pairing computations, which improves the efficiency of communication and computation, and it is more suitable for the applications in resource-constrained network environment.

With the rapid development of quantum computing technology, traditional collaborative signature schemes based on RSA and elliptic curve cryptography face significant security challenges. This paper proposes a lattice-based certificateless collaborative signature scheme (L-CCS) to address the security and efficiency requirements of multi-party collaboration in intelligent computing and network systems. By leveraging lattice problems such as the Small Integer Solution and Learning With Errors, our scheme ensures post-quantum security. The L-CCS eliminates the need for a trusted Key Generation Center and a dedicated aggregator, enhancing decentralization and system robustness. Our construction achieves existential unforgeability under adaptive chosen-message attacks in the random oracle model. Furthermore, we provide a practical implementation optimized for large-scale data sharing, demonstrating sublinear scalability in signature size and computation time.