Certificateless Encryption Scheme Research Articles

Leakage-Resilient Anonymous Multireceiver Certificateless Encryption Resistant to Side-Channel Attacks

Anonymous multireceiver encryption (AMRE) allows a data provider to transmit a ciphertext to a designated group of receivers. Any receiver of the designated group can get the plaintext by decrypting this ciphertext while the receiver's identity is concealed to other receivers. In the past, several anonymous multireceiver certificateless encryption (AMR-CLE) schemes based on the certificateless public-key cryptography (CL-PKC) were proposed to remove both the certificate management problem of AMRE schemes based on the conventional public-key cryptography and the key escrow problem of AMR-IBE schemes based on the ID-based public-key cryptography. Recently, side-channel attacks endanger the existing cryptographic schemes, AMRE, AMR-IBE, AMR-CLE, etc. To resist to such attacks, leakage-resilient cryptography is a novel way. However, until now, there exists no multireceiver encryption or AMRE scheme resistant to side-channel attacks. In this article, we present the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$first$</tex-math></inline-formula> leakage-resilient anonymous multireceiver certificateless encryption (LR-AMR-CLE) scheme. In our scheme, attackers are granted to repeatedly extract fractional content of each secret key participated in our scheme and retains the original security of AMR-CLE schemes.

Certificateless encryption scheme with provable security in the standard model suitable for mobile devices

Public key encryption is an important method to ensure data security. In recent years, researchers have designed multiple certificateless encryption (CLE) schemes, and the security proofs of most known schemes are done in random oracle model (ROM). It is generally known that the standard model (SM) is more reliable than the ROM. Currently, there are only three CLE schemes with provable security in SM. Unfortunately, all three schemes require pairing operations, enjoy high computation costs, and are not suitable for mobile devices. In this paper, we constructed a new CLE scheme. Compared with other schemes, the new scheme is with two advantages: First, the security proofs of the new scheme are done in SM. Second, the new scheme does not use pairing operation and enjoys higher computation efficiency. Efficiency analysis shows that the computation cost of the new scheme is only 12.4% of that of the most efficient scheme known, which is suitable for mobile devices.

Cryptanalysis of a Certificateless Hybrid Signcryption Scheme and a Certificateless Encryption Scheme for Internet of Things

In wireless and mobile networks with limited storage and computing resources, certificateless cryptography has more advantages because of its low dependence on infrastructure and short security parameters. Recently, Gong et al. and Karati et al., respectively, proposed a new certificateless scheme in the Internet of Things environment, one of which is a certificateless hybrid signcryption scheme, and the other’s basis is a certificateless encryption scheme. Gong et al. and Karati et al. gave the formal security proof for their schemes, respectively. In this article, the attack algorithms against these two schemes are presented separately, thus proving that their schemes are insecure and not suitable for the Internet of Things environment.

Leakage-Resilient Revocable Certificateless Encryption with an Outsourced Revocation Authority

To resolve both certificate management and key escrow problems, a certificateless public-key system (CLPKS) has been proposed. However, a CLPKS setting must provide a revocation mechanism to revoke compromised users. Thus, a revocable certificateless public-key system (RCLPKS) was presented to address the revocation issue and, in such a system, the key generation centre (KGC) is responsible to run this revocation functionality. Furthermore, a RCLPKS setting with an outsourced revocation authority (ORA), named RCLPKS-ORA setting, was proposed to employ the ORA to alleviate the KGC’s computational burden. Very recently it was noticed that adversaries may adopt side-channel attacks to threaten these existing conventional public-key systems (including CLPKS, RCLPKS and RCLPKS-ORA). Fortunately, leakage-resilient cryptography offers a solution to resist such attacks. In this article, the first leakage-resilient revocable certificateless encryption scheme with an ORA, termed LR-RCLE-ORA scheme, is proposed. The proposed scheme is formally shown to be semantically secure against three types of adversaries in the RCLPKS and RCLPKS-ORA settings while resisting side-channel attacks. In the proposed scheme, adversaries are allowed to continually extract partial ingredients of secret keys participated in various computational algorithms of the proposed scheme while retaining its security.

An Efficient Pairing-Free Identity-Based Certificateless Signcryption

A certificateless (CL) signcryption scheme is a cryptographic primitive that provides user authentication and message confidentiality at the same time. CL signcryption schemes (as a type of certificateless encryption scheme) have solved problems concerning malicious server presentation, and the server who issues users' partial private keys and certificates cannot obtain users' signing keys. Therefore, the CL signcryption scheme is an excellent choice for protecting users' signing keys and providing user authentication and message confidentiality. Moreover, signcryption schemes have lower computational costs than signature and encryption schemes. The present study presents a short and efficient CL signcryption scheme based on the hyperelliptic curve (HC). Applying HC as the calculation base for designing the presented CL signcryption scheme reduces key-length from 160 bits to 80. The presented CL signcryption scheme is shorter than other recently-proposed ones with regard to communication overhead with its less than one-third shorter length compared to the shortest of the others. Moreover, it is more efficient than other recently-proposed CL signcryption schemes in the user-side computational cost, including the textit{key generation} and textit{user key generation} phases that have been halved in total. Finally, the security of the presented CL signcryption scheme was analyzed in the random oracle (RO) model based on the hardness of the point factorization problem (PFP) on HC.

A certificateless encryption scheme based on blockchain

The normal public key encryption system has complicated certificate management and key escrow problems, while the certificateless encryption system does no longer require certificates, which reduces storage space and communication costs. As a result, the certificateless encryption system has acquired enormous attention from the academic community, but there are two types of attacks that stop it from being broadly used in manufacturing and life. Because of its tamper proof and autonomy, blockchain is helpful to resist these two kinds of attacks. Therefore, this paper proposes an encryption scheme combining blockchain technology and certificateless encryption technology. This scheme can not only make certificateless encryption scheme resist these two attacks, but also decrease the storage space of blockchain and resolve the complex certificate management problems. Related experimental consequences prove that our scheme can correctly resist the two types of attacks confronted by means of certificateless encryption systems and resolve the key escrow problem.

Provably secure certificateless encryption scheme in the standard model

Recently, numerous certificateless encryption (CLE) schemes have been introduced. The security proofs of most schemes are given under the random oracle model (ROM). In the standard model, the adversary is able to calculate the hash function instead of asking the challenger. Currently, there is only one scheme that was proved to be secure in SM. In this paper, we constructed a new CLE scheme and gave the security proofs in SM. In the new scheme, the size of the storage space required by the system is constant. The computation cost is lower than other CLE schemes due to it needs only two pairing operations.

Comments on “Revocable and Scalable Certificateless Remote Authentication Protocol With Anonymity for Wireless Body Area Networks”

To solve security and privacy issues in wireless body area networks, several types of digital signature schemes have been adapted to a number of authentication protocols. Recently in IEEE TRANSACTIONS ON INFORMATION FORENSICS AND SECURITY (TIFS) (DOI: 10.1109/TIFS.2015.2414399), Xiong and Qin proposed a revocable certificateless encryption (R-CLE) scheme against decryption key exposure, and a revocable certificateless signature (R-CLS) scheme against signing key exposure. Then they proposed a revocable and scalable certificateless remote authentication protocol with anonymity for wireless body area networks based on the combination of R-CLE scheme and R-CLS scheme. However, we show that their RCLS scheme is insecure against type I adversaries: a type I adversary who knows only a user’s secret value can forge signatures on any messages in the same time period. Hence, their authentication protocol fails to meet the claimed security requirements.

Privacy-Aware Secure Anonymous Communication Protocol in CPSS Cloud Computing

Cloud computing has emerged as a promising paradigm for the Internet of Things (IoT) and Cyber-Physical-Social Systems (CPSS). However, the problem of how to ensure the security of data transmission and data storage in CPSS is a key issue to address. We need to protect the confidentiality and privacy of users’ data and users’ identity during the transmission and storage process in CPSS. In order to avoid users’ personal information leakage from IoT devices during the process of data processing and transmitting, we propose a certificateless encryption scheme, and conduct a security analysis under the assumption of Computational Diffie-Hellman(CDH) Problem. Furthermore, based on the proposed cryptography mechanism, we achieve a novel anonymous communication protocol to protect the identity privacy of communicating units in CPSS. In the new protocol, an anonymous communication link establishment method and an anonymous communication packet encapsulation format are proposed. The Diffie-Hellman key exchange algorithm is used to construct the anonymous keys distribution method in the new link establishment method. And in the new onion routing packet encapsulation format, the session data are firstly separated from the authentication data to decrease the number of cryptography operations. That is, by using the new onion routing packet we greatly reduces the encryption operations and promotes the forwarding efficiency of anonymous messages, implementing the privacy, security and efficiency in anonymous communication in cyber-physical-social systems.

Designated tester certificateless encryption with keyword search

In this paper, we introduce the notion of designated tester certificateless encryption with keyword search (dCLEKS) and define the required security model. In the defined security model, in addition to the security of ciphertexts, we consider the security of trapdoors through which the security against offline keyword guessing attack (oKGA) is ensured. We further propose a concrete dCLEKS scheme and show that it is secure in the defined security model under the intractability of GBDH and CDH problems. To the best of our knowledge, the proposed dCLEKS scheme is the only secure searchable certificateless encryption scheme that provides security against oKGA performed by outside attackers and does not require secure channels for transmission of ciphertexts and trapdoors between users and the server.

A New Certificateless Signature Scheme Provably Secure in the Standard Model

Certificateless cryptography eliminates the need of certificates from public-key cryptography and solves the key escrow problem in identity-based cryptography. Since Al-Riyami and Paterson introduced the concept of certificateless cryptography, there have been several proposals for certificateless encryption schemes and signature schemes provably secure in the random oracle model. In the random oracle paradigm, the schemes make use of cryptographic hash functions that are modeled as random oracles in the security proof. However, it has been shown that when random oracles are instantiated with concrete hash functions, the schemes may not be secure. Afterward, several certificateless signature (CLS) schemes provably secure without random oracles have been proposed. However, it turned out that all the schemes are insecure against type I or II adversaries. In this paper, we propose a new CLS scheme secure in the standard model under the computational Diffie–Hellman assumption. We then investigate the practical feasibility of our scheme.

A revocable certificateless encryption scheme with high performance

Featuring no key escrow and no certificate, certificateless public key cryptography (CLPKC) has received much attention. A necessary problem in CLPKC is how to revoke a compromised/misbehaving user, which still remains to be efficiently solved: all existing methods are not practical for use owing to either enormous computation (secret channels), or a costly mediator. In this paper, we present a new approach for revocation in CLPKC and give a revocable certificateless encryption (RCLE) scheme. In the new scheme, a user's private key contains three parts: an initial partial private key, a time key and a secret value. The time key is updated at every time period and is transmitted over a public channel. Our construction offers higher performance than previous solutions. Based on the bilinear Diffie-Hellman problem, our RCLE scheme is provably secure in the random oracle model.

A revocable certificateless encryption scheme with high performance

Featuring no key escrow and no certificate, certificateless public key cryptography (CLPKC) has received much attention. A necessary problem in CLPKC is how to revoke a compromised/misbehaving user, which still remains to be efficiently solved: all existing methods are not practical for use owing to either enormous computation (secret channels), or a costly mediator. In this paper, we present a new approach for revocation in CLPKC and give a revocable certificateless encryption (RCLE) scheme. In the new scheme, a user's private key contains three parts: an initial partial private key, a time key and a secret value. The time key is updated at every time period and is transmitted over a public channel. Our construction offers higher performance than previous solutions. Based on the bilinear Diffie-Hellman problem, our RCLE scheme is provably secure in the random oracle model.

Efficient Anonymous Multireceiver Certificateless Encryption

To protect receiver privacy, researchers constructed anonymous multireceiver encryption by implanting anonymity in multireceiver encryption. It allows a sender to produce the identical ciphertext for multiple designated receivers. Every designated receiver can decrypt the ciphertext, but does not know who the other designated receivers are. Recently, several anonymous multireceiver identity (ID)-based encryption (AMIBE) schemes were proposed without the utilization of certificates. However, these AMIBE schemes are not efficient because their decryption cost of each receiver grows linearly with the number of the designated receivers. Moreover, all the ID-based cryptographic schemes suffer from the key escrow problem, which has been resolved by using certificateless public key settings. Very recently, Islam et al. proposed an anonymous multireceiver certificateless encryption (AMCLE) scheme. However, the encryption cost of a sender is quadric with the number of designated receivers, whereas the decryption cost of each receiver is linear with the number. In this paper, we propose an efficient AMCLE scheme with constant decryption cost, namely, the required decryption cost of each receiver is independent of the number of receivers. When compared with previously proposed AMIBE and AMCLE schemes, our scheme solves the key escrow problem and improves the efficiency of encryption/decryption significantly as well.

Certificateless encryption secure against selective opening attack

AbstractThe notion of selective opening attacks (SOAs) was first introduced by Dwork et al. at FOCS'99. Informally, an encryption scheme is SOA secure if an adversary is given a vector of ciphertexts and can adaptively corrupt some fraction of them by obtaining not only their messages but also their randomness, the uncorrupted ciphertexts retain secure. Provably achieving security against SOA has been proven extremely challenging. In this paper, we propose a security model to capture simulation‐based selective opening chosen‐plaintext attacks (SIM‐SO‐CPA) for certificateless encryption. We provide a concrete construction and prove its security in our simulation‐based selective opening chosen‐plaintext attack security model, based on the real or random and computational Diffie–Hellman assumptions. Compared with previous SOA‐secure public key encryption and identity‐based encryption, our certificateless encryption scheme is more simple and efficient. Copyright © 2017 John Wiley &amp; Sons, Ltd.

A Novel Approach on Certificateless Encryption Schemes

A Novel Approach on Certificateless Encryption Schemes

MEDIATED CERTIFICATELESS CRYPTOSYSTEM FOR THE SECURITY OF DATA IN PUBLIC CLOUD

Security is a serious issue in cloud computing. Encryption is the solution for the security in cloud. There are many encryption techniques. Each one has its own merits and demerits. In the case of identity based encryption it is free from security mediator, predefined keys are there, and have the problem of key escrow and certificate revocation. Then the arrival of mediated certificateless scheme eliminates the key escrow problem, and certificate revocation problem. In certificateless encryption scheme, key generation process is divided in between the user and the cloud. In our system data owner encrypt the data using its secret key. Then the data owner encrypt the secret key twice. Hence formed intermediate keys. Then send this encrypted data and intermediate keys to cloud. The cloud partially decrypt the intermediate key and send partially decrypted data and encrypted data to required user. The user decrypt the partialy decrypted data. Then the user will get the required key for decryption. so the user can decrypt it completly.The main advantage of our system is, the data owner can send same data to multiple clients with minimum cost.

Revocable and Scalable Certificateless Remote Authentication Protocol With Anonymity for Wireless Body Area Networks

To ensure the security and privacy of the patient's health status in the wireless body area networks (WBANs), it is critical to secure the extra-body communication between the smart portable device held by the WBAN client and the application providers, such as the hospital, physician or medical staff. Based on certificateless cryptography, this paper proposes a remote authentication protocol featured with nonrepudiation, client anonymity, key escrow resistance, and revocability for extra-body communication in the WBANs. First, we present a certificateless encryption scheme and a certificateless signature scheme with efficient revocation against short-term key exposure, which we believe are of independent interest. Then, a certificateless anonymous remote authentication with revocation is constructed by incorporating the proposed encryption scheme and signature scheme. Our revocation mechanism is highly scalable, which is especially suitable for the large-scale WBANs, in the sense that the key-update overhead on the side of trusted party increased logarithmically in the number of users. As far as we know, this is the first time considering the revocation functionality of anonymous remote authentication for the WBANs. Both theoretic analysis and experimental simulations show that the proposed authentication protocol is provably secure in the random oracle model and highly practical.

Efficient revocable certificateless encryption against decryption key exposure

Certificateless public key cryptosystem (CLPKC) improves the identity based public key cryptosystem to be key-escrow free. Many research works on CLPKC have been presented so far. However, the revocation problem in CLPKC still lacks effective solutions. The current revocation approaches suffer from either low efficiency or security weakness. In this study, we propose the first ‘scalable revocable’ certificateless encryption (RCLE) scheme against ‘decryption key exposure’. The scheme is provably secure in the standard model. Moreover, we give a second interesting RCLE scheme whose decryption key is very short.

An Efficient Certificateless Encryption for Secure Data Sharing in Public Clouds

We propose a mediated certificateless encryption scheme without pairing operations for securely sharing sensitive information in public clouds. Mediated certificateless public key encryption (mCL-PKE) solves the key escrow problem in identity based encryption and certificate revocation problem in public key cryptography. However, existing mCL-PKE schemes are either inefficient because of the use of expensive pairing operations or vulnerable against partial decryption attacks. In order to address the performance and security issues, in this paper, we first propose a mCL-PKE scheme without using pairing operations. We apply our mCL-PKE scheme to construct a practical solution to the problem of sharing sensitive information in public clouds. The cloud is employed as a secure storage as well as a key generation center. In our system, the data owner encrypts the sensitive data using the cloud generated users' public keys based on its access control policies and uploads the encrypted data to the cloud. Upon successful authorization, the cloud partially decrypts the encrypted data for the users. The users subsequently fully decrypt the partially decrypted data using their private keys. The confidentiality of the content and the keys is preserved with respect to the cloud, because the cloud cannot fully decrypt the information. We also propose an extension to the above approach to improve the efficiency of encryption at the data owner. We implement our mCL-PKE scheme and the overall cloud based system, and evaluate its security and performance. Our results show that our schemes are efficient and practical.