Efficient Forward and Provably Secure ID-Based Signcryption Scheme with Public Verifiability and Public Ciphertext Authenticity

Signcryption is a cryptographic primitive that performs encryption and signature in a single logical step, at lower computational cost and communication over heads than the signature-then-encryption. Proxy signcryption schemes are variations of ordinary signcryption schemes and have been useful in many applications where the delegation of rights is quite common. By combining the functionalities of proxy signature scheme and signcryption scheme, in this paper, we proposed a new ID-based proxy signcryption scheme which offers both public verifiability and forward security. The security requirements and performance of the proposed scheme are analyzed.

Signcryption is a useful cryptographic primitive which simultaneously performs encryption and signature with cost less than the signature-then-encryption approach. Identity-based signcryption (IBSC) eliminates the complicated management of certificates in signcryption schemes in the traditional public-key infrastructure (PKI) setting. Most IBSC schemes are constructed in the random oracle model, while it is unknown how to instantiate a really ``random oracle in the real world. By exploiting Boneh et al.'s strongly unforgeable signature and Paterson et al.'s identity-based signature, this paper proposes a new IBSC scheme in the standard model. It is proven that our IBSC scheme satisfies semantic security and strong unforgeability under the bilinear decision Diffie-Hellman (BDDH) assumption. The proofs do not rely on random oracles. Performance analysis shows that our scheme is also efficient and practical.

Signcryption is an important cryptography primitive that provides confidentiality and authenticity for the messages simultaneously, at lower costs than traditional sign-then-encrypt method. This paper presents the attacks against two identity-based signcryption schemes: the Zhang et al.'s assertion signcryption scheme in decentralized autonomous environments, which is not consistent in multi-PKG scenarios, and the Yu et al.'s identity-based signcryption scheme in the standard model, which cannot achieve indistinguishability against chosen plaintext attacks.

Signcryption is a cryptographic technique that provides both confidentiality and authenticity of data during public transmission in many modern applications like Internet -of -Things (IoT), Wireless Sensor Networks (WSNs) etc. The functionalities of encryption and Signature can achieve simultaneously through the signcryption with lower computational cost and communication overheads than those of traditional sign-then-encrypt approach. Many signcryption schemes have been constructed by various researchers in different cryptographic frameworks. Certificateless cryptography is one of the recent public key cryptography which eliminates the key escrow problem and complex certificate management problemsin identity based cryptography and traditional public key cryptography respectively. Providing the security and efficiency in many modern applications including IoT and WSNs is a crucial task. In this paper, we proposed new signcryption scheme in certificateless cryptography. This scheme supports the property of public verifiability and is secure against various types of adversaries in the random oracle model with the assumption that the Computational Diffie-Hellman Problem (CDHP) and the Elliptic Curve Discrete Logarithmic Problems (ECDLP) are hard. Due to pairing-free environment the proposed scheme is computationally more efficient than the existing public verifiable signcryption schemes.

In this paper, we present a new identity based signcryption scheme with public verifiability using quadratic residue and pairings over elliptic curves, and give a security proof about the original scheme in the random oracle model. Furthermore, this paper focuses on a multisender(t,n) identity based threshold sighcryption. Finally, we prove the scheme of threshold setting is secure as the original scheme.

According to most existing identity-based ring signcryption schemes are based on random oracle model and have too many pairings, a new efficient identity-based ring signcryption scheme is proposed. It can satisfy the unconditional anonymity of the sender by using symmetric encryption algorithm and reduce the pairings by skillfully setting public parameters. Its indistinguishability under adaptive chosen ciphertext attack is proofed by the intractability of the DBDH problem and the unforgeability under adaptive chosen message attack is proved by the intractability of the CDH problem.

A new ID-based (t,n) threshold signcryption scheme is proposed based on identity and discrete logarithm problem in finite field. By using Lagrange Interpolation Formula, the new scheme not only has the function of threshold signature, but also has the function of hiding message and designating verifier. So this scheme has authentication, secrecy, data integrity and privacy of signers, it can be used in the situation of multi-user cooperation.

Authentication and encryption technology are the core components of the DRM (Digital Rights Management) system. In this paper, a security protocol basing on the identity-based signcryption scheme is proposed to implement these technologies simultaneously. According to the comparison with the PKI (public key infrastructure)-based DRM system, the advantages of this protocol are proved. However, in practice the application of the identity-based cryptosystems is limited by the key escrow and distribution problems. In order to solve these problems, we proposed a new self-certified identity-based signcryption scheme, in which partial data chosen by the users are added to the private key. This scheme is proved that it can successfully avoid the key escrow and distribution problems, and is more secure and effective in practice.

Self-sustaining, efficient and forward-secure cryptographic constructions for Unattended Wireless Sensor Networks

We present a concrete identity-based broadcast group-receiver encryption and signcryption scheme respectively based on Gentry's IBE scheme to achieve confidentiality and authentication during content distribution. A sender can send a secure message just by using the receive group's identity information, even before the receiver in the designated group obtains his private key from a PKG. Every member of the receiving group needs to keep only one private key and can decrypt the ciphertext independently; Both ciphertexts and system parameters are of constant size.

Signcryption was first proposed by Zheng and there after several signcryption schemes have been formulated. The broadcast scheme for Zheng does not offer non repudiation using public verification. A latest research by Elkamchouchi et. al proposed a new signcryption scheme for the broadcast environment. The scheme is known as Signcryption Multiple-Recipients Variant (SMRV). From the detail analysis of the scheme, it is observed that confidentiality of the information is lost when the parameters are sent to the third party for verification. Thus the scheme violates the basic property of security. Upon further analysis it is seen that the computational cost of the scheme can be reduced by eliminating few unnecessary steps which do not strengthen the security of the scheme but introduces an extra computational cost. In this paper an efficient and improved signcryption scheme for the broadcast environment is presented. The presented scheme is more efficient than Zheng's and Elkamchouchi et. al scheme in terms of computational cost. The scheme offers non repudiation through public verification and confidentiality of the information is also ensured.

Often clients (e.g., sensors, organizations) need to outsource joint computations that are based on some joint inputs to external untrusted servers. These computations often rely on the aggregation of data collected from multiple clients, while the clients want to guarantee that the results are correct and, thus, an output that can be publicly verified is required. However, important security and privacy challenges are raised, since clients may hold sensitive information. In this paper, we propose an approach, called verifiable additive homomorphic secret sharing (VAHSS), to achieve practical and provably secure aggregation of data, while allowing for the clients to protect their secret data and providing public verifiability i.e., everyone should be able to verify the correctness of the computed result. We propose three VAHSS constructions by combining an additive homomorphic secret sharing (HSS) scheme, for computing the sum of the clients’ secret inputs, and three different methods for achieving public verifiability, namely: (i) homomorphic collision-resistant hash functions; (ii) linear homomorphic signatures; as well as (iii) a threshold RSA signature scheme. In all three constructions, we provide a detailed correctness, security, and verifiability analysis and detailed experimental evaluations. Our results demonstrate the efficiency of our proposed constructions, especially from the client side.

With the pervasiveness of the Internet of Things (IoT) and the rapid progress of wireless communications, Wireless Body Area Networks (WBANs) have attracted significant interest from the research community in recent years. As a promising networking paradigm, it is adopted to improve the healthcare services and create a highly reliable ubiquitous healthcare system. However, the flourish of WBANs still faces many challenges related to security and privacy preserving. In such pervasive environment where the context conditions dynamically and frequently change, context-aware solutions are needed to satisfy the users' changing needs. Therefore, it is essential to design an adaptive access control scheme that can simultaneously authorize and authenticate users while considering the dynamic context changes. In this paper, we propose a context-aware access control and anonymous authentication approach based on a secure and efficient Hybrid Certificateless Signcryption (H-CLSC) scheme. The proposed scheme combines the merits of Ciphertext-Policy Attribute-Based Signcryption (CP-ABSC) and Identity-Based Broadcast Signcryption (IBBSC) in order to satisfy the security requirements and provide an adaptive contextual privacy. From a security perspective, it achieves confidentiality, integrity, anonymity, context-aware privacy, public verifiability, and ciphertext authenticity. Moreover, the key escrow and public key certificate problems are solved through this mechanism. Performance analysis demonstrates the efficiency and the effectiveness of the proposed scheme compared to benchmark schemes in terms of functional security, storage, communication and computational cost.

Ring signcryption enables a user to send a message confidentially and authentically to a specific receiver in an anonymous way. In this paper a new identity-based ring signcryption scheme (IBRSC) from pairings was presented, which was proven to be satisfied with IND-CCA2 and EUF-CMA security formally. A comparison with current two influential schemes proposed by Huang et al. and by Selvi et al. respectively shows that our scheme which has the shortest cipertext is much more efficient than the former and no less than the latter.

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.