Adaptive Chosen Ciphertext Attack Research Articles

Bilinear Pairing-Based Hybrid Signcryption for Secure Heterogeneous Vehicular Communications

Vehicular ad-hoc networks (VANETs) enable vehicles to exchange safety information with the surrounding vehicles and infrastructure in order to ensure safety and efficiency in traffic management. Recently however, vehicles come from different manufacturers and therefore use different protocols for the transmission of messages. As a result, communication among vehicles become heterogeneous. Because of this, VANETs face problems related to security and performance. To address this, some heterogeneous vehicular communication-based schemes have been proposed. However, they do not perform well because of an increase in computational overhead. In order to resolve this, we propose a certificateless cryptosystem (CLC) and public key infrastructure (PKI)-based conditional privacy-preserving hybrid signcryption (CP-CPPHSC) scheme. This scheme utilizes bilinear pairings and provides security requirements in a single logical step. Through the CP-CPPHSC scheme, a message is transmitted by a vehicle using the CLC to a vehicle using the PKI. Additionally, the CP-CPPHSC scheme supports the batch unsigncryption method which helps a vehicle to unsigncrypt more than one messages simultaneously. In the random oracle model (ROM), our scheme ensures existential unforgeability against adaptive chosen message attack (EUF-CMA) with respect to a hardness assumption of q-strong Diffie-Hellman (q-SDH) and modified inverse computational Diffie-Hellman (mICDH) problems and indistinguishability against adaptive chosen ciphertext attack (IND-CCA2) with respect to a hardness assumption of q-bilinear Diffie-Hellman inversion (q-BDHI) problem. Our scheme effectively reduces computational cost when compared to state-of-the-art schemes without an increase in the communication cost.

An IND-CCA2 Secure Certificateless Hybrid Signcryption

This article proposes a hybrid certificateless signcryption scheme that is secure against adaptive chosen ciphertext adversary in the random oracle model. The scheme combines an asymmetric encryption which is one way against chosen plaintext attack and any One-Time secure symmetric encryption scheme, combined using Fujisaki–Okamoto transformation. Uncommon to many Fujisaki–Okamoto based constructions which ensure message integrity alone, this scheme provides entity authentication in addition. By the choice of a hash function that utilizes the advantage of sponge based construction, the scheme enables the user to incorporate any One-Time secure symmetric encryption by re-configuring the input/output parameters. Fujisaki–Okamoto transformation, which is currently a standard in hybrid constructions, guarantees the indistinguishability against adaptive chosen ciphertext attack. The provision for choosing symmetric encryption in the scheme enables it to be implemented in all sort of cryptographic requirements including those in wireless communication.

A Compact Hardware Implementation of CCA-Secure Key Exchange Mechanism CRYSTALS-KYBER on FPGA

Post-quantum cryptosystems should be prepared before the advent of powerful quantum computers to ensure information secure in our daily life. In 2016 a post-quantum standardization contest was launched by National Institute of Standards and Technology (NIST), and there have been lots of works concentrating on evaluation of these candidate protocols, mainly in pure software or through hardware-software co-design methodology on different platforms. As the contest progresses to third round in July 2020 with only 7 finalists and 8 alternate candidates remained, more dedicated and specific hardware designs should be considered to illustrate the intrinsic property of a certain protocol and achieve better performance. To this end, we present a standalone hardware design of CRYSTALS-KYBER, amodule learning-with-errors (MLWE) based key exchange mechanism (KEM) protocol within the 7 finalists on FPGA platform. Through elaborate scheduling of sampling and number theoretic transform (NTT) related calculations, decent performance is achieved with limited hardware resources. The way that Encode/Decode and the tweaked Fujisaki-Okamoto transform are implemented is demonstrated in detail. Analysis about minimizing memory footprint is also given out. In summary, we realize the adaptive chosen ciphertext attack (CCA) secure Kyber with all selectable module dimension k on the smallest Xilinx Artix-7 device. Our design computes key-generation, encapsulation (encryption) and decapsulation (decryption and reencryption) phase in 3768/5079/6668 cycles when k = 2, 6316/7925/10049 cycles when k = 3, and 9380/11321/13908 cycles when k = 4, consuming 7412/6785 LUTs, 4644/3981 FFs, 2126/1899 slices, 2/2 DSPs and 3/3 BRAMs in server/client with 6.2/6.0 ns critical path delay, outperforming corresponding high level synthesis (HLS) based designs or hardware-software co-designs to a large extent.

Efficient Certificateless Signcryption Scheme for Wireless Sensor Networks in Ubiquitous Healthcare Systems

With the current developments in wireless networks, the use of Wireless sensor networks (WSNs) in the medical field has attracted a lot of attention. WSNs are being used to collect and transmit patient physiological information in ubiquitous healthcare systems. One of the major challenges in healthcare systems is security and privacy of patients’ vital data. By its very nature, a wireless sensor network provides a resource constrained environment and sensor nodes used in WSNs are limited in terms resource usage. Keeping data secure in a resource constraint environment is an important and challenging task. Hence, the need for secure and more efficient cryptosystems. In this paper, we are proposing a secure pairing-free certificateless signcryption scheme for use in ubiquitous healthcare systems. We compare the efficiency of our proposed scheme with other related signcryption schemes. A formal security proof for indistinguishability against adaptive chosen ciphertext attack and unforgeability against adaptive chosen message attack for our scheme is presented in random oracle model.

A lightweight and provable secure identity-based generalized proxy signcryption (IBGPS) scheme for Industrial Internet of Things (IIoT)

Recently, the Industrial Internet of Things (IIoT) has become increasingly important for applications in the industry. IIoT has essentially become a prime security focus for implementing secure communication. Among the available cryptographic tools, identity-based signcryption provide a sound solution to fulfill the security requirement of IIoT. On the other hand a generalized proxy signcryption can work adaptively as proxy signature and proxy signcryption using a single algorithm. In order to accomplish effective and on-time communication whenever the manager of the company went out for a usual business trip or an IIoT device which has lack of resources, then it must need to delegate her/his signcryption rights to their subordinates (proxy agents/device). For this purpose, to make the delegation procedure more efficient and reliable, we proposed a lightweight identity-based generalized proxy signcryption (IBGPS) scheme for IIoT. The IBGPS scheme is provably secure in terms of indistinguishability against adaptive chosen ciphertext attack (IND − IBGPS − CCA) and existential unforgeable against a possible adaptive chosen message attack (EUF − IBGPS − CMA) under Hyperelliptic Curve Decisional Diffie-Hellman problem (HEDHP) and Hyperelliptic Curve Discrete Logarithm problem (HECDLP) in the random oracle model. Furthermore the performance evaluation in terms of computation and communication costs shows that the IBGPS scheme is more effective than the existing schemes.

Privacy-Enhancing Group Signcryption Scheme

In the last decades, several signcryption schemes have been developed for different privacy-enhancing purposes. In this paper, we propose a new privacy-enhancing group signcryption scheme that provides: unforgeability, confidentiality, ciphertext and sender anonymity, traceability, unlinkability, exculpability, coalition-resistance, and unforgeable tracing verification. It is important to notice that the proposed scheme allows a signer to anonymously signcrypt a message on the group’s behalf (i.e., sender’s anonymity). The security analysis of the scheme is also provided. Our proposal is proven to be strongly existentially unforgeable under an adaptive chosen message attack, indistinguishable under an adaptive chosen ciphertext attack, and to provide ciphertext anonymity under an adaptive chosen ciphertext attack. Furthermore, the scheme is extended to work in a multi-receiver scenario, where an authorized group of receivers is able to unsigncrypt the ciphertext. The experimental results show that our scheme is efficient even on computationally restricted devices and can be therefore used in many IoT applications. The Signcrypt protocol on smart cards takes less than 1 s (including communication overhead). The time of the Unsigncrypt protocol on current ARM devices is negligible (less than 40 ms).

Practical Identity Based Online/Off-Line Signcryption Scheme for Secure Communication in Internet of Things

Contemporary developments in providing proper security in the Internet of Things (IoT) have been made signcryption scheme highly suitable for various applications such as smart cities, smart healthcare and smart agriculture. However, security and privacy are the primary concerns in protecting data as it was highly sensitive. This paper is proposing a new Identity based online/off-line signcryption scheme suitable to provide secure message communication among IoT devices, gateway, and the server. This method is divided into the online and offline phases, where heavy mathematical computations are carried out in the offline phase and light computations in the online phase. This scheme provides a security solution for integrating Wireless Sensor Networks (WSNs) into the IoT. Experimentation was done and finally compared against existing techniques and proved that the proposed mechanism reduces the computation time in online by performing a greater number of operations in off-line signcryption phase. Further, it provides indistinguishability against adaptive chosen ciphertext attacks and existential unforgeability against adaptive chosen messages attacks.

An Efficient and Provable Secure Certificate-Based Combined Signature, Encryption and Signcryption Scheme for Internet of Things (IoT) in Mobile Health (M-Health) System.

Mobile health (M-Health) system is the remote form of Wireless Body Area Networks (WBAN), which can be used for collecting patient's health data in real-time with mobile devices, and storing it to the network servers. The data can be accessed by doctors to monitor, diagnosed and treat patients through a variety of techniques and technologies. The main advantage of the M-Health system is the ease of time-independent communication from physically distant places that enhances the quality of healthcare services at a reduced cost. Furthermore, to provide faster access to the treatment of patients, an M-Health system can be integrated with the internet of things (IoT) to offer preventive or proactive healthcare services by connecting devices and persons. However, its equally great drawback lies in transmitting and receiving the health information wirelessly through an open wireless medium that offers different security and privacy violation threats. We aim to address such a deficiency, and thus a new scheme called an efficient and provable secure certificate-based combined signature, encryption and signcryption (CBCSES) scheme, has been proposed in this article. The scheme not only obtains encryption and signcryption but also provides encryption or signature model alone when needed. To show the effectiveness of the proposed scheme, detailed security analyses, i.e. indistinguishable under adaptive chosen-ciphertext attacks (IND-CBCSES-CCA) and unforgeable under adaptive chosen message attacks (EUF-CBCSES-CMA), and the comparisons with relevant existing schemes are carried out. The results obtained authenticate the superiority of our scheme in terms of both computation and communication costs with enhanced security.

Equality test with an anonymous authorization in cloud computing

With the rapid popularity and wide adoption of cloud storage, providing privacy-preserving by protecting sensitive information becomes a matter of grave concern. The most effective and sensible way to address this issue is to encrypt the data before uploading it to the cloud. However, to search over encrypted data with different keys is still an open problem when it comes to the deployment of emerging technologies such as healthcare applications and e-marketplace systems. To address these issues, in this paper, we proposed a secure and efficient public-key encryption with an equality test technique that supports anonymous authorization, abbreviated as (PKEET-AA). Our proposed scheme allows a specific user to identify who can perform the equality test process among various cloud servers without compromising sensitive information. It also provides an anonymous approach to search for some statistical information about specific identical encrypted records in several databases. Moreover, we prove that our proposed PKEET-AA scheme is one-way secure against chosen-ciphertext attack (OW-CCA) and undistinguishable against adaptive chosen ciphertext attack (IND-CCA) in the random oracle model. Thus, to provide authorization/multi-authorization anonymity under the Decisional Diffie–Hellman assumption.

An Efficient Hybrid Signcryption Scheme With Conditional Privacy-Preservation for Heterogeneous Vehicular Communication in VANETs

Vehicular ad hoc networks (VANETs) ensure improvement in road safety and traffic management by allowing the vehicles and infrastructure that are connected to them to exchange safety messages. Due to the open wireless communication channels, security and privacy issues are a major concern in VANETs. A typical attack consists of a malicious third party intercepting, modifying and retransmitting messages. Heterogeneous vehicular communication in VANETs occurs when vehicles (only) or vehicles and other infrastructure communicate using different cryptographic techniques. To address the security and privacy issues in heterogeneous vehicular communication, some heterogeneous signcryption schemes have been proposed. These schemes simultaneously satisfy the confidentiality, authentication, integrity and non-repudiation security requirements. They however fail to properly address the efficiency with respect to the computational cost involved in unsigncrypting ciphertexts, which is often affected by the speeds at which vehicles travel in VANETs. In this paper, we propose an efficient conditional privacy-preserving hybrid signcryption (CPP-HSC) scheme that uses bilinear pairing to satisfy the security requirements of heterogeneous vehicular communication in a single logical step. Our scheme ensures the transmission of a message from a vehicle with a background of an identity-based cryptosystem (IBC) to a receiver with a background of a public-key infrastructure (PKI). Furthermore, it supports a batch unsigncryption method, which allows the receiver to speed up the process by processing multiple messages simultaneously. The security of our CPP-HSC scheme ensures the indistinguishability against adaptive chosen ciphertext attack (IND-CCA2) under the intractability assumption of q -bilinear Diffie-Hellman inversion ( q -BDHI) problem and the existential unforgeability against adaptive chosen message attack (EUF-CMA) under the intractability assumption of q -strong Diffie-Hellman ( q -SDH) problem in the random oracle model (ROM). The performance analysis indicates that our scheme has an improvement over the existing related schemes with respect to the computational cost without an increase in the communication cost.

An alternative practical public-key cryptosystems based on the Dependent RSA Discrete Logarithm Problems

In this paper, an alternative public-key cryptosystems (PKCs) are proposed based on the new algebraic problems namely “Dependent RSA Discrete Logarithm Problems” derived from the RSA and Discrete Logarithm (DLog) assumptions together. These PKCs are provably secure for the notions of security: indistinguishable encryptions under chosen-plaintext attacks (IND-CPA), and adaptive chosen-ciphertext attacks (IND-CCA2). Initially, a new algebraic “Computational-Dependent RSA Discrete Logarithm Problem” is presented. Then, its variant named “Decisional-Dependent RSA Discrete Logarithm Problem” is presented. Thereafter, a specific discussion has been done about their hardness and their relations to each other. Also, some arguments are given to validate the cryptographic purpose of these problems. Next, using this decisional variant an efficient PKC: “Dependent RSA Discrete Logarithm” (DRDL) cryptosystem that has indistinguishable encryptions under chosen-plaintext attacks, in the standard model is presented. Further, a PKC variant: DRDL-1 cryptosystem with improved security properties that has indistinguishable encryptions under adaptive chosen-ciphertext attacks using this decisional variant in the random oracle model, with a low computational cost is presented. These new algebraic problems constructed by using the apparent hardness of RSA and Discrete Logarithm (DLog) problems are helpful in combining both efficiency and security. Hence, it becomes more efficient than all the cryptosystems specially designed for the ElGamal cryptosystem to make it indistinguishable encryptions under adaptive chosen-ciphertext attacks.

Anonymous Certificate-Based Broadcast Encryption With Personalized Messages

Broadcast encryption with personalized messages (BEPM) is a newly proposed cryptographic primitive, which supports a broadcaster to deliver the common encrypted broadcast message to a group of authorized users. It also supports a broadcaster to deliver the personalized messages to the individual authorized users simultaneously. However, none of the existing BEPM schemes consider the anonymity of authorized users, which is a crucial security requirement for many BEPM application scenarios. Besides, the previous studies on BEPM only achieve security against chosen-plaintext attack adversaries. Certificate-based cryptosystem gives a viable way to construct more secure and efficient BEPM schemes. We propose the new concept of anonymous certificate-based broadcast encryption with personalized messages (ANON-CBBE-PM). Subsequently, we illustrate the formal definition and the security model of ANON-CBBE-PM. Furthermore, we present an ANON-CBBE-PM scheme, which solves key escrow problem in identity-based cryptosystem and certificate management problem in traditional public key cryptosystem. Compared with the existing BEPM schemes, the proposed scheme not only protects the privacy of authorized users, but also has advantage in performance. To be more specific, the lengths of the user secret key and the system public parameters, as well as the cost for decryption are constant. For those BEPM applications with a multitude of users whose computing ability is limited, the proposed scheme is more practical. In addition, our scheme simultaneously achieves anonymity and confidentiality under adaptive chosen-ciphertext attack in the standard model.

Security Analysis of an Enhanced Certificateless Signcryption in the Standard Model

Quite recently, Luo and Wan putted forward a new certificateless signcryption (CLSC) scheme with low computation cost in the standard model. They stated that their newly proposed scheme achieves the unforgeability against adaptive chosen message attack (i.e, unforgeability) and indistinguishability against adaptive chosen ciphertext attack (i.e., confidentiality). However, we find that the scheme cannot reach the claimed security feature. Specifically, in this paper, we will demonstrate that in Luo and Wan’s CLSC scheme, the plaintext can be easily recovered from the ciphertext by ordinary attacker and malicious-but-passive KGC. In addition, we identify that this scheme even cannot resist forgery attack of a malicious KGC.

Practical continuous leakage-resilient CCA secure identity-based encryption

Leakage of private information including private keys of user has become a threat to the security of computing systems. It has become a common security requirement that a cryptographic scheme should withstand various leakage attacks. In the real life, an adversary can break the security of cryptography primitive by performing continuous leakage attacks. Although, some research on the leakage-resilient cryptography had been made, there are still some remaining issued in previous attempts. The identity-based encryption (IBE) constructions were designed in the bounded-leakage model, and might not be able to meet their claimed security under the continuous-leakage attacks. In the real applications, the leakage is unbounded. That is, a practical cryptography scheme should keep its original security in the continuous leakage setting. The previous continuous leakage-resilient IBE schemes either only achieve chosen-plaintext attacks security or the chosen-ciphertext attacks (CCA) security is proved in the selective identity model. Aiming to solve these problems, in this paper, we show how to construct the continuous leakage-resilient IBE scheme, and the scheme’s adaptive CCA security is proved in the standard model based on the hardness of decisional bilinear Diffie-Hellman exponent assumption. For any adversary, all elements in the ciphertext are random, and an adversary cannot obtain any leakage on the private key of user from the corresponding given ciphertext. Moreover, the leakage parameter of our proposal is independent of the plaintext space and has a constant size.

Enhanced-visual-cryptography-based optical information hiding system

Recent years, with the rapid development of information technology, the information security has received more and more attention. A variety of encryption methods to protect the information have been reported. Visual cryptography is one of the encryption methods, which has highly security because of its threshold feature. And the cryptographic information can be explained by a naked eye in the decryption process. In the application of visual cryptography, however, each shared image is limited to transparency films and overlapping on computer. In our previous work, we proposed the scheme of invisible visual cryptography and developed the visual-cryptography-based optical hiding system (VCOH), which transformed the conventional visual cryptography shares into diffraction optical elements (DOEs). It not only increases the application range of visual cryptography, but also enhances security. In this paper, we propose an optical information hiding system based on the extended visual cryptography, which inherits the concept of invisible visual cryptography. In contrast to our previous work, the method proposed in this work can hide a meaningful image instead of text messages. Meanwhile, the capacity and imperceptibility of the method are greatly increased. The hiding process of the system contains two steps. Firstly, the secret image is converted into meaningful shares through the extended visual cryptography algorithm. Secondly, the meaningful shares are able to hide in phase-keys through an iterative phase retrieval algorithm, such as Gerchberg-Saxton algorithm and Yang-Gu iterative algorithm. Then the phase-keys can be made into diffraction optical elements (DOEs) to store and transport in a physical way. In the decryption process, DOEs are illuminated with the laser beam to reconstruct the meaningful shares. The secret image can be explained by the direct overlapping of the reconstructed shares without any optical or cryptographic knowledge. The simulation and optical experimental results show that the proposed method has good performance of security and validate the feasibility of the proposed method. Besides, in this paper the robustness and security issues are also analyzed. This system has a high security because of its indistinguishability under adaptive chosen ciphertext attack (IND-CCA2) security. Additionally, this system is relatively less robust than the VCOH because it shares meaningful images with highly complex and detailed structures.

Revocable Certificateless Public Key Encryption With Outsourced Semi-Trusted Cloud Revocation Agent

Certificateless public key cryptography (CL-PKC) not only eliminates the need for certificates in traditional certificate-based PKC but also solves the inherent key escrow problem in identity-based PKC. However, an unsolved but critical issue in CL-PKC is how to revoke a misbehaving user. Some revocable certificateless public key encryption (RCL-PKE) schemes have been proposed, but these schemes have two main drawbacks: 1) public key uniqueness is not guaranteed, thus allowing the existence of multiple copies of each initial secret key. 2) The existing outsourced RCL-PKE schemes place excessive trust in the cloud server, which may continue to update decryption keys stealthily for misbehaving users. In this paper, we address these issues by proposing a novel RCL-PKE with semi-trusted cloud revocation agents (s-CRAs). We describe the framework and the security model for the RCL-PKE with s-CRA and prove that the proposed scheme is semantically secure against adaptive chosen-ciphertext attacks under the bilinear Diffie-Hellman assumption in the random oracle model. Furthermore, we compare the proposed scheme with previous RCL-PKE schemes in terms of performance and robustness. The evaluation results show that the proposed scheme achieves public key uniqueness and reliable revocation flexibility at low computational and communication costs.

A Novel CCA-Secure Verifiable Authenticated Encryption Scheme Using BSDH and q-SDH Assumptions

When it comes to secure transactions online, the requirements of confidentiality and authenticity are usually concerned the most. The former prevents unauthorized reading, while the latter ensures authorized access. Hybrid cryptographic mechanisms such as authenticated encryption (AE) schemes, simultaneously combine the functions of public key encryption and digital signature. Some AE schemes also provide a cost-free arbitration mechanism to deal with the signer’s later repudiation. Such schemes have been found to have numerous practical applications like on-line credit card transactions, confidential contract signing and the protection of digital evidence, etc. However, a designated verifier should also have the ability to convince any third party that he/she is indeed the intended recipient. In this paper, the author presents a novel verifiable authenticated encryption (VAE) scheme with the functionality of recipient proof. Furthermore, the paper shows that the proposed VAE scheme is non-delegatable and provably secure under the random oracle proof models. A non-delegatable hybrid cryptographic scheme provides a higher security level even if the shared common key is compromised. Specifically, the author of the paper will demonstrate that the designed construction is proved secure against adaptive chosen-ciphertext attacks (CCA2) assuming the hardness of Bilinear Square Diffie-Hellman Problem (BSDHP) and secure against adaptive chosen-message attacks (CMA) assuming the hardness of q-Strong Diffie-Hellman Problems (q-SDHP).

Identity‐based encryption resilient to continuous key leakage

Leakage of private information has become a threat to the security of computing systems. It has become a common security requirement that a cryptography scheme should withstand various leakage attacks, even the continuous leakage attacks. However, in the current constructions on the (continuous) leakage-resilient identity-based encryption (CLR-IBE) scheme, the leakage parameter is a fixed value. Aiming to solve these problems, in this study, the authors show how to construct the CLR-IBE scheme, and the adaptive chosen-ciphertext attacks security of proposed construction can be proved in the standard model. To further improve the practicability of CLR-IBE scheme, they design an improved IBE scheme with continuous leakage amplified property, and the leakage parameter has an arbitrary length.

Cryptanalysis of an Authentication Scheme Using an Identity Based Generalized Signcryption

Secure data transmission is a challenging issue in modern data communication. ID based generalized signcryption is a cost effective security primitive which provides authentication or confidentiality, or jointly confidentiality and authentication. Wei’s proposed an ID based generalized signcryption scheme for authentication and confidentiality of big data in a standard model, claiming that their scheme holds the security of indistinguishability against adaptive chosen-ciphertext attacks and existential unforgeability against adaptive chosen message attacks. In this paper, we analyzed Wei’s scheme by launching security attacks on the scheme to check its validity. As a result, it became clear and proved that the master secret key generated in the scheme is compromisable. Similarly, the mentioned scheme does not hold the security of indistinguishability against adaptive chosen-ciphertext attacks and existential unforgeability against adaptive chosen message attacks. Consequently, Wei’s schemes is prone to attacks and is insecure.

Improvement of an outsourced attribute-based encryption scheme

Attribute-based encryption (ABE) scheme has become an important technology in cryptography. However, the considerable overhead of encryption and decryption restricts its application on the devices with limited resource. Fortunately, as the development of cloud computing, someone presents that outsourcing decryption and encryption can be used to deal with the problem. This idea has drawn a lot of attention after being proposed. Recently, Li et al. put forward an efficient verifiable outsourced ABE scheme which outsources the encryption and decryption to the cloud server and enables its valid receivers to verify the correctness of the message after decrypting. However, in this paper, we prove that their scheme is not secure under chosen plaintext attack which is the basic security requirement of ABE scheme. Then, we improve their scheme and illustrate that the improved scheme is adaptive chosen ciphertext attack (CCA2) secure in the random oracle model. The final comparison shows that we do not add extra computational burden to improve the security.