Efficient and Provably-secure Certificateless Strong Designated Verifier Signature Scheme without Pairings

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

An Efficient Certificate-Based Designated Verifier Signature Scheme

Certificate-based public key cryptography not only solves certificate revocation problem in traditional PKI but also overcomes key escrow problem inherent in identity-based cryptosystems. This new primitive has become an attractive cryptographic paradigm. In this paper, we propose the notion and the security model of certificate-based designated verifier signatures (CBDVS). We provide the first construction of CBDVS and prove that our scheme is existentially unforgeable against adaptive chosen message attacks in the random oracle model. Our scheme only needs two pairing operations, and the signature is only one element in the bilinear group G1. To the best of our knowledge, our scheme enjoys shortest signature length with less operation cost

Certificateless Public Auditing Protocol with Constant

To provide the integrity of outsourced data in the cloud storage services, many public auditing schemes which allow a user to check the integrity of the outsourced data have been proposed. Since most of the schemes are constructed on Public Key Infrastructure (PKI), they suffer from several concerns like management of certificates. To resolve the problems, certificateless public auditing schemes also have been studied in recent years. In this paper, we propose a certificateless public auditing scheme which has the constant-time verification algorithm. Therefore, our scheme is more efficient than previous certificateless public auditing schemes. To prove the security of our certificateless public auditing scheme, we first define three formal security models and prove the security of our scheme under the three security models

A supplement to Liu et al.\u27s certificateless signcryption scheme in the standard model

Recently, Liu et al. proposed the first certificateless signcryption scheme without random oracles and proved it was semantically secure in the standard model. However, Selvi et al. launched a fatal attack to its confidentiality by replacing users\u27 public keys, thus pointed out this scheme actually doesn\u27t reach the semantic security as claimed. In this paper, we come up with a rescue scheme based on Liu et al.\u27s original proposal. A Schnorr-based one-time signature is added to each user\u27s public key, which is used to resist Selvi et al.\u27s attack. In addition, according to the mistake made in Liu et al.\u27s security proof, we also show that our improvement is really secure in the standard model under the intractability of the decisional bilinear Diffie-Hellman assumption

Toward an RSU-unavailable lightweight certificateless key agreement scheme for VANETs

Vehicle ad-hoc networks have developed rapidly these years, whose security and privacy issues are always concerned widely. In spite of a remarkable research on their security solutions, but in which there still lacks considerations on how to secure vehicle-to-vehicle communications, particularly when infrastructure is unavailable. In this paper, we propose a lightweight certificateless and one-round key agreement scheme without pairing, and further prove the security of the proposed scheme in the random oracle model. The proposed scheme is expected to not only resist known attacks with less computation cost, but also as an efficient way to relieve the workload of vehicle-to-vehicle authentication, especially in no available infrastructure circumstance. A comprehensive evaluation, including security analysis, efficiency analysis and simulation evaluation, is presented to confirm the security and feasibility of the proposed scheme

A Strong and Efficient Certificateless Digital Signature Scheme

This paper extends the certificateless public key infrastructure model that was proposed by Hassouna et al by proposing new digital signature scheme to provide true non-repudiation, the proposed signature scheme is short and efficient, it is also has strength point that the KGC has no contribution in signature generation/verification process, therefore any compromise of the KGC does not affect the non-repudiation service of the system. Furthermore, even the KGC cannot do signature forgery by (temporary) replacing the user’s public key

A Computationally Efficient Online/Offline Signature Scheme for Underwater Wireless Sensor Networks

Underwater wireless sensor networks (UWSNs) have emerged as the most widely used wireless network infrastructure in many applications. Sensing nodes are frequently deployed in hostile aquatic environments in order to collect data on resources that are severely limited in terms of transmission time and bandwidth. Since underwater information is very sensitive and unique, the authentication of users is very important to access the data and information. UWSNs have unique communication and computation needs that are not met by the existing digital signature techniques. As a result, a lightweight signature scheme is required to meet the communication and computa‑ tion requirements. In this research, we present a Certificateless Online/Offline Signature (COOS) mechanism for UWSNs. The proposed scheme is based on the concept of a hyperelliptic curves cryptosystem, which offers the same degree of security as RSA, bilinear pairing, and elliptic curve cryptosystems (ECC) but with a smaller key size. In addition, the proposed scheme was proven secure in the random oracle model under the hyperelliptic curve discrete logarithm problem. A se‑ curity analysis was also carried out, as well as comparisons with appropriate current online/offline signature schemes. The comparison demonstrated that the proposed scheme is superior to the exist‑ ing schemes in terms of both security and efficiency. Additionally, we also employed the fuzzy‑based Evaluation‑based Distance from Average Solutions (EDAS) technique to demonstrate the effective‑ ness of the proposed scheme.publishedVersio

Certificateless Signatures: Structural Extensions of Security Models and New Provably Secure Schemes

Certificateless signatures (CLSs) were introduced to solve the key escrow problem of identity-based signatures. In CLS, the full private key is determined by neither the user nor the trusted third party. However, a certificate of a public key is not required in CLS schemes; therefore, anyone can replace the public key. On the formal security, there are two types of adversaries where the Type I adversary acts as the outsider, and the Type II as the key generation center. Huang et al. took a few security issues into consideration and provided some security models. They showed three kinds of Type I adversaries with different security levels. Moreover, Tso et al. found the existence of another Type I adversary that was not discussed by Huang et al.; however, the adversaries are still too subtle to be presently defined. In this paper, we further consider public key replacement and strong unforgeability in certificateless signatures. All feasible situations are revisited along with abilities of adversaries. Additionally, structural extensions of security models are proposed with respect to the described public key replacement and strong unforgeability. Moreover, we also present some schemes, analyze their security against different adversaries, and describe our research results. Finally, one of the proposed certificateless short signature schemes is proven to achieve the strongest security level

A COMPREHENSIVE STUDY OF CRYPTOGRAPHY AND KEY MANAGEMENT BASED SECURITY IN CLOUD COMPUTING

Cloud computing is a cost effective flexible and proven delivery platform for providing consumer IT services or business services over internet. It has an ability to provide many services over internet. It not only provides computing services but additional computing resources. To interact with various services in the cloud and to store retrieve data from cloud several security mechanism is required. Cryptography and key management mechanism are one of the import services in the cloud to secure data. In this context, this paper investigates the basic problem of cloud computing with cryptography and key management system for enabling support of interoperability between cloud cryptography client and key management services