CGST: Provably Secure Lightweight Certificateless Group Signcryption Technique Based on Fractional Chaotic Maps

In recent years, there has been a lot of research interest in analyzing chaotic constructions and their associated cryptographic structures. Compared with the essential combination of encryption and signature, the signcryption scheme has a more realistic solution for achieving message confidentiality and authentication simultaneously. However, the security of a signcryption scheme is questionable when deployed in modern safety-critical systems, especially as billions of sensitive user information is transmitted over open communication channels. In order to address this problem, a lightweight, provably secure certificateless technique that uses Fractional Chaotic Maps (FCM) for group-oriented signcryption (CGST) is proposed. The main feature of the CGST-FCM technique is that any group signcrypter may encrypt data/information with the group manager (GM) and have it sent to the verifier seamlessly. This implies the legitimacy of the signcrypted information/data is verifiable using the public conditions of the group, but they cannot link it to the conforming signcrypter. In this scenario, valid signcrypted information/data cannot be produced by the GM or any signcrypter in that category alone. However, the GM is allowed to reveal the identity of the signcrypter when there is a legal conflict to restrict repudiation of the signature. Generally, the CGST-FCM technique is protected from the indistinguishably chosen ciphertext attack (IND-CCA). Additionally, the computationally difficult Diffie-Hellman (DH) problems have been used to build unlinkability, untraceability, unforgeability, and robustness of the projected CGST-FCM scheme. Finally, the security investigation of the presented CGST-FCM technique shows appreciable consistency and high efficiency when applied in real-time security applications

Lightweight certificateless and provably-secure signcryptosystem for the internet of things

International audienceIn this paper, we propose an elliptic curve-based signcryption scheme derived from the standardized signature KCDSA (Korean Certificate-based Digital Signature Algorithm) in the context of the Internet of Things. Our solution has several advantages. First, the scheme is provably secure in the random oracle model. Second, it provides the following security properties: outsider/insider confidentiality and unforgeability; non-repudiation and public verifiability, while being efficient in terms of communication and computation costs. Third, the scheme offers the certificateless feature, so certificates are not needed to verify the user's public keys. For illustration, we conducted experimental evaluation based on a sensor Wismote platform and compared the performance of the proposed scheme to concurrent scheme

Cryptanalysis of Certificateless Signcryption Schemes and an Efficient Construction Without Pairing

Certificateless cryptography introduced by Al-Riyami and Paterson eliminates the key escrow problem inherent in identity based cryptosystems. Even though building practical identity based signcryption schemes without bilinear pairing are considered to be almost impossible, it will be interesting to explore possibilities of constructing such systems in other settings like certificateless cryptography. Often for practical systems, bilinear pairings are considered to induce computational overhead. Signcryption is a powerful primitive that offers both confidentiality and authenticity to noteworthy messages. Though some prior attempts were made for designing certificateless signcryption schemes, almost all the known ones have security weaknesses. Specifically, in this paper we demonstrate the security weakness of the schemes in \cite{BF08}, \cite{DRJR08} and \cite{CZ08}. We also present the first provably secure certificateless signcryption scheme without bilinear pairing and prove it in the random oracle model

On the Security of a Certificateless Strong Designated Verifier Signature Scheme

Recently, Chen et al. proposed the first non-delegatable certificateless strong designated verifier signature scheme and claimed that their scheme achieves all security requirements. However, in this paper, we disprove their claim and present a concrete attack which shows that their proposed scheme is forgeable. More precisely, we show that there exist adversaries who are able to forge any signer\u27s signature for any designated verifier on any message of his choice

Cryptanalysis of a certificateless aggregate signature scheme

Recently, Nie et al. proposed a certificateless aggregate signature scheme. In the standard security model considered in certificateless cryptography, we are dealing with two types of adversaries. In this paper, we show that Nie et al.\u27s scheme is insecure against the adversary of the first type. In other words, although they claimed that their proposed scheme is existentially unforgeable against adaptive chosen message attack considering the adversaries in certificateless settings, we prove that such a forgery can be done

Generic Construction of Certificateless Signcryption Scheme

Confidentiality and message authentication are the most important security goals that can be achieved simultaneously by Signcryption scheme. It is a cryptographic technique that performs both the functions of digital signature and public key encryption in a single logical step significantly at a lower cost than that of conventional method of signature-then-encryption. The paper proposes an efficient Certificateless Signcryption Scheme(CLSC) in random oracle model on bilinear mapping. It is provably secure under the assumptions of intractability of k-CAA, Inv-CDH, q-BDHI and CDH problems

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

Cryptanalysis and improvement of certificateless aggregate signature with conditional privacy-preserving for vehicular sensor networks

Secure aggregate signature schemes have attracted more concern due to their wide application in resource constrained environment. Recently, Horng et al. [S. J. Horng et al., An efficient certificateless aggregate signature with conditional privacy-preserving for vehicular sensor networks, Information Sciences 317 (2015) 48-66] proposed an efficient certificateless aggregate signature with conditional privacy-preserving for vehicular sensor networks. They claimed that their scheme was provably secure against existential forgery on adaptively chosen message attack in the random oracle model. In this paper, we show that their scheme is insecure against a malicious-but-passive KGC under existing security model. Further, we propose an improved certificateless aggregate signature

Efficient Certificateless Online/Offline Signature

Abstract Public key cryptography usually is computationally more expensive than symmetric key systems. Due to this low power or resource constrained devices cannot make use of public key cryptosystems easily. There is a need for high security in these devices since many of these devices perform complex tasks which includes interaction with third party cloud infrastructures. These cloud infrastructures are not trusted entities. Hence there is need for light weight public key cryptography which are secure against these cloud administrators. The trusted entity in certificateless schemes cannot compromise the security of the users. Online/offline have two parts, first the computationally heavy part(offline) of the cryptosystem and then the main "online" algorithm for use on resource constrained devices. The heavy computations are done in the offline phase on a more powerful device. Hence, Certificateless online/offline schemes are perfect for low power devices interacting with clouds. In this paper, we present a certificateless online/offline signature scheme. This scheme is the most efficient certificateless signature scheme in existence and also has the added advantage of being online/offline. The scheme is proven secure in the random oracle model