Group Key Exchange Research Articles

Forward Secure Offline Assisted Group Key Exchange From Isogeny-Based Blinded Key Encapsulation Mechanism

<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Group key exchange</i> is a promising cryptographic protocol that has been studied extensively over the years. However, an overwhelming majority of them involve interaction among users. This makes them unsuitable in a cloud-based outsourced storage systems where users seek to store and share their files with their collaborators who stay offline until they want to access the file. To address this concern, Boyd et al. designed an <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">offline assisted group key exchange</i> (OAGKE) protocol that offers forward secrecy. The core component of their OAGKE protocol is a variant of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">key encapsulation mechanism</i> (KEM) called <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">blinded</i> KEM (BKEM). However, their constructions of BKEM are susceptible to quantum attacks. This work proposes an <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">isogeny-based</i> BKEM and a <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">forward secure</i> OAGKE that is secure against adversaries equipped with quantum computers. Our construction of BKEM is based on the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Commutative Supersingular Isogeny Diffie-Hellman</i> (CSIDH) cryptosystem. We provide a formal security proof demonstrating the security of our scheme. Furthermore, we manifest an instantiation of our BKEM from CSIDH-512 parameter set. Finally, we present our isogeny-based OAGKE protocol along with its rigorous security analysis.

Leveraging Smart Contracts for Secure and Asynchronous Group Key Exchange Without Trusted Third Party

Leveraging Smart Contracts for Secure and Asynchronous Group Key Exchange Without Trusted Third Party

A group key exchange and secure data sharing based on privacy protection for federated learning in edge‐cloud collaborative computing environment

SummaryFederated learning (FL) is widely used in internet of things (IoT) scenarios such as health research, automotive autopilot, and smart home systems. In the process of model training of FL, each round of model training requires rigorous decryption training and encryption uploading steps. The efficiency of FL is seriously affected by frequent encryption and decryption operations. A scheme of key computation and key management with high efficiency is urgently needed. Therefore, we propose a group key agreement technique to keep private information and confidential data from being leaked, which is used to encrypt and decrypt the transmitted data among IoT terminals. The key agreement scheme includes hidden attribute authentication, multipolicy access, and ciphertext storage. Key agreement is designed with edge‐cloud collaborative network architecture. Firstly, the terminal generates its own public and private keys through the key algorithm then confirms the authenticity and mapping relationship of its private and public keys to the cloud server. Secondly, IoT terminals can confirm their cryptographic attributes to the cloud and obtain the permissions corresponding to each attribute by encrypting the attributes. The terminal uses these permissions to encrypt the FL model parameters and uploads the secret parameters to the edge server. Through the storage of the edge server, these ciphertext decryption parameters are shared with the other terminal models of FL. Finally, other terminal models are trained by downloading and decrypting the shared model parameters for the purpose of FL. The performance analysis shows that this model has a better performance in computational complexity and computational time compared with the cited literature.

Secure post‐quantum group key exchange: Implementing a solution based on Kyber

AbstractQuantum computing poses fascinating challenges for current cryptography, threatening the security of many schemes and protocols widely used today. To adapt to this reality, the U.S. National Institute for Standards and Technology (NIST) is currently running a standardization process in search of post‐quantum (classical, yet resistant to quantum attacks) cryptographic tools, focusing on signature schemes and key encapsulation mechanisms. Many of the competing proposals also include designs for two‐party key exchange, which can be combined in different ways to fit scenarios involving parties, that is, yielding group key exchange protocols. However, very few implementations of such group protocols are available to practitioners, which face a non‐trivial challenge when deciding how to implement a protocol for establishing secure group sessions in this new post‐quantum scenario. With this in mind, the authors report on the implementation of a secure post‐quantum group key exchange protocol in the so‐called Quantum Random Oracle Model. The protocol decided to implement is based on a KEM called Kyber, which is one of the finalists of the NIST competition. Not only this group construction is the only one available in the literature using a NIST finalist, but also, among all post‐quantum designs the authors are aware of, it uses this strongest security model (as, e.g. in other proposals, the adversarial interaction with the hash functions of the system is assumed to be exclusively classical). Furthermore, experimental evidence is provided supporting this choice in terms of performance, even if the number of involved entities is large (up to 2000). All data and code are publicly available.

Member Tampering Attack on Burmester-Desmedt Group Key Exchange Protocol and Its Countermeasure

With the rapid development of cloud computing and mobile networks, more and more application scenarios require a secret group key for secure communication. Group Key Exchange (GKE) protocol provides a secret group key for three or more members. Burmester and Desmedt presented an influential GKE protocol, which has a broadcast version and a cyclic version. In this paper, we investigate the security weaknesses of the Burmester-Desmedt protocol. We report that both the broadcast version and the cyclic version of the Burmester-Desmedt protocol suffer member tampering attacks if the two members that belong to both group A and group B are corrupted. That is, two corrupted members can add some unknowing members of group A to group B and trick the legal members of group B to believe that these unknowing members share the secret group key with them after a protocol run. Furthermore, to defeat the member tampering attack, we propose digital signature-based improvements on the broadcast version and the cyclic version of the Burmester-Desmedt protocol. We hope our research results will encourage the development of more robust and effective GKE protocols that stand rigorous security analysis.

FSEE: A Forward Secure End-to-End Encrypted Message Transmission System for IoT

Leakage of long-term secrets is a major concern when cryptographic schemes are implemented on devices with weak protection capability, especially for resource-constrained IoT devices. Forward secrecy is a means to minimize the damage when such an event takes place. For pub-/sub-based IoT systems, several end-to-end (from publisher to subscriber) encrypted message transmission schemes have been proposed to tackle the confidentiality problems brought by malicious message brokers. But none of them provide forward secrecy. This article presents FSEE, a forward secure end-to-end encrypted message transmission system for pub-/sub-based IoT. To support FSEE, we design a novel group key exchange protocol BA-GKE, which relies on a semi-trusted key exchange server to provide forward secrecy and support asynchronous communication between group members. We prove its forward secrecy by ProVerif. The core idea of FSEE is to establish a forward secure symmetric key per device using BA-GKE asynchronously, and this device-specific key is shared with the device and its authorized subscribers for encrypting messages securely. By adding a semi-trusted key exchange server to realize BA-GKE in the current IoT architecture, FSEE does not need to change the existing message broker and could be deployed incrementally. The experimental results show that FSEE has comparable performance to existing prominent research and provides higher security.

Medical cooperative authenticated key agreement schemes with involvement of personal care assistant in telemedicine

Background and objectiveDue to the mature development of information and network technology, telemedicine is increasingly able to facilitate the implementation of long-term care for patients with disabilities. Such patients may, however, not be adept at usage of such technological products, thus personal care assistants (PCAs) are required to assist in such usage. While PCAs collaborate with patients in operating telehealth systems, such use also poses challenges to security and raises concerns involving the authenticity of all the related participants. Even mutual authentication between patients and physicians can be a challenge when patients change or have multiple physicians, which raises key management concerns. MethodsA cooperative authenticated key agreement scheme is developed to address the various security scenarios when providing telemedicine care to patients with a disability. In addition, an enhanced version scheme with group key exchange functionality is proposed to satisfy situations where more than one physician is involved in providing services during a medical consultation situation. ResultsThe proposed schemes achieve the scenarios of PCAs involvement and group consultation in telemedicine with perfect security properties including mutual authentication, session key agreement, forward secrecy, known-key security, impersonation attack prevention, replay attack prevention, and insider attack prevention. The performance analysis is demonstrated to show the feasibility of our schemes. ConclusionsTwo schemes are presented for a patient with a disability in a telemedicine scenario. The first scheme establishes a solution for a typical situation where the patient and a personal care assistant cooperatively log into the telemedicine system and achieve a key agreement with the designated physician. Considering the case of multiple physicians’ collaboration, the second scheme provides a solution by forming a group for the patient and physicians and then distributes a group key between the group members to set up a secure communication platform.

Information Fusion in Autonomous Vehicle Using Artificial Neural Group Key Synchronization.

Information fusion in automated vehicle for various datatypes emanating from many resources is the foundation for making choices in intelligent transportation autonomous cars. To facilitate data sharing, a variety of communication methods have been integrated to build a diverse V2X infrastructure. However, information fusion security frameworks are currently intended for specific application instances, that are insufficient to fulfill the overall requirements of Mutual Intelligent Transportation Systems (MITS). In this work, a data fusion security infrastructure has been developed with varying degrees of trust. Furthermore, in the V2X heterogeneous networks, this paper offers an efficient and effective information fusion security mechanism for multiple sources and multiple type data sharing. An area-based PKI architecture with speed provided by a Graphic Processing Unit (GPU) is given in especially for artificial neural synchronization-based quick group key exchange. A parametric test is performed to ensure that the proposed data fusion trust solution meets the stringent delay requirements of V2X systems. The efficiency of the suggested method is tested, and the results show that it surpasses similar strategies already in use.

Authenticated Tree-Based R-LWE Group Key Exchange

Abstract We present the first constant round, multicast, authenticated tree-based R-LWE group key exchange protocol with logarithmic communication and memory complexity. Our protocol achieves post-quantum security through a reduction to a Diffie–Hellman-like analogue to the decisional R-LWE problem. We also present a sequential version with constant memory complexity but a logarithmic number of rounds and communication complexity.

ID‐based group key exchange mechanism for virtual group with microservice

Currently, research on network functions virtualization focuses on using microservices in cloud environments. Previous studies primarily focused on communication between nodes in physical infrastructure. Until now, there is no sufficient research on group key management in virtual environments. The service is composed of microservices that change dynamically according to the virtual service. There are dependencies for microservices on changing the group membership of the service. There is also a high possibility that various security threats, such as data leakage, communication surveillance, and privacy exposure, may occur in interactive communication with microservices. In this study, we propose an ID-based group key exchange (idGKE) mechanism between microservices as one group. idGKE defines the microservices' schemes: group key gen, join group, leave group, and multiple group join. We experiment in a real environment to evaluate the performance of the proposed mechanism. The proposed mechanism ensures an essential requirement for group key management such as secrecy, sustainability, and performance, improving virtual environment security.

Fast and Efficient Group Key Exchange in Controller Area Networks (CAN)

The security of vehicle communication buses and electronic control units has received much attention in the recent years. However, while essential for practical deployments, the problem of securely exchanging cryptographic keys between electronic control units on the CAN bus received little attention so far. In this work, we evaluate group extensions of a regular key exchange protocol, i.e., the elliptic curve version of the Diffie-Hellman protocol, by using both a standardized NIST elliptic curve as well as the faster, more recently proposed Four <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mathbb {Q}$</tex-math></inline-formula> curve. We deploy protocol implementations and determine crisp performance bounds on real-world automotive-grade platforms with Infineon and ARM cores. For an up-to-date analysis, we use both CAN and its more recent extension CAN-FD as communication layers. Roughly, the computational runtime of the key exchange protocol scales logarithmically or linearly with the number of nodes, depending on the protocol version. The computational time proves to be more critical than bandwidth due to the more demanding elliptic curve operations.

Authenticated logarithmic-order supersingular isogeny group key exchange

We present the first constant-round, tree-based, group key exchange protocol based on SIDH with logarithmic-order communication and memory complexity, where the only previous isogeny-based group key exchange, SIBD, has linear-order communication and memory complexity. We call our protocol the supersingular isogeny tree-based group key exchange (SIT). We show that our protocol satisfies post-quantum security through a reduction to the supersingular decisional Diffie–Hellman (SSDDH) problem in the security model of Manulis, Suzuki, and Ustaoglu. We also construct a peer-to-peer (sequential) version of SIT. Finally, we present a compiler that turns SIT into an authenticated group key exchange while maintaining the same complexity and security as SIT, resulting in the authenticated SIT group key exchange (A-SIT).

Computation and communication efficient secure group key exchange protocol for low configuration system

The group key exchange protocol is a cryptographic mechanism is designed to provide a common session key for a group, there are some common challenges to this type of algorithm as computation and communication cost. Whenever the involvement of high computation and communication operations to the algorithms encounter, then the system with low configuration always faces problem in major time delay. The proposed approach is designed specifically to provide computation and communication efficient algorithms for low configuration systems without violating the security. For making our approach computationally efficient, we replaced modular exponential operation by modular multiplication operation, helpful for low configuration system making task early. For making our approach communication efficient, we used the divide and conquer mechanism to reduced the message transmission cost. The major task is to generate a common session key for the group in less computation time for a low configuration system without violating the security. The RSA algorithm assuring security with constant computation cost while the modular multiplication operation, assuring the less computation cost for low configuration system. The major limitation of the study as the approach is more efficient and applicable for low configuration system only, if comparing the existing approaches with the low configuration system.

Compiled Constructions towards Post-Quantum Group Key Exchange: A Design from Kyber

A group authenticated key exchange (GAKE) protocol allows a set of parties belonging to a certain designated group to agree upon a common secret key through an insecure communication network. In the last few years, many new cryptographic tools have been specifically designed to thwart attacks from adversaries which may have access to (different kinds of) quantum computation resources. However, few constructions for group key exchange have been put forward. Here, we propose a four-round GAKE which can be proven secure under widely accepted assumptions in the Quantum Random Oracle Model. Specifically, we integrate several primitives from the so-called Kyber suite of post-quantum tools in a (slightly modified) compiler from Abdalla et al. (TCC 2007). More precisely, taking as a starting point an IND-CPA encryption scheme from the Kyber portfolio, we derive, using results from Hövelmanns et al. (PKC 2020), a two-party key exchange protocol and an IND-CCA encryption scheme and prove them fit as building blocks for our compiled construction. The resulting GAKE protocol is secure under the Module-LWE assumption, and furthermore achieves authentication without the use of (expensive) post-quantum signatures.

Design and Implementation of Constant-Round Dynamic Group Key Exchange from RLWE

Group Key Exchange (GKE) is required for secure group communication with high confidentiality. In particular, a trusted authority can handle issues that happen by the malicious actions of group members, but it is expensive to deploy and not suitable in a dynamic setting where the network requires frequent membership status changes. To overcome these issues, we designed yet another quantum-resistant constant-round GKE based on lattice without a trusted authority based on Apon et al.'s protocol (PQCrypto 2019) by modifying their key computation phase. Then, we describe the novel dynamic authenticated GKE (called DRAG) with membership addition/deletion procedures in Ring Learning with Errors (RLWE) setting, while the former ones are built from Diffie-Hellman problem. Under the specific adversary who can leak the long-term secret key from the party, we suggest a rigorous proof of DRAG in the random oracle model based on the hardness assumption of RLWE problem and the property of Renyi divergence. As a proof of concept, implementation details are described to meet level 1 NIST security. Our implementation is reasonable for practical use since the total runtime to get a group secret key takes about 3 msec and it can be considered as a reference implementation of other quantum-resistant GKEs.

Password–Authenticated Group Key Establishment from Smooth Projective Hash Functions

Abstract Password-authenticated key exchange (PAKE) protocols allow users sharing a password to agree upon a high entropy secret. Thus, they can be implemented without complex infrastructures that typically involve public keys and certificates. In this paper, a provably secure password-authenticated protocol for group key establishment in the common reference string (CRS) model is presented. While prior constructions of the group (PAKE) can be found in the literature, most of them rely on idealized assumptions, which we do not make here. Furthermore, our protocol is quite efficient, as regardless of the number of involved participants it can be implemented with only three communication rounds. We use a (by now classical) trick of Burmester and Desmedt for deriving group key exchange protocols using a two-party construction as the main building block. In our case, the two-party PAKE used as a base is a one-round protocol by Katz and Vaikuntanathan, which in turn builds upon a special kind of smooth projective hash functions (KV-SPHFs). Smooth projective hash functions (SPHFs) were first introduced by Cramer and Shoup (2002) as a valuable cryptographic primitive for deriving provable secure encryption schemes. These functions and their variants proved useful in many other scenarios. We use here as a main tool a very strong type of SPHF, introduced by Katz and Vaikuntanathan for building a one-round password based two party key exchange protocol. As evidenced by Ben Hamouda et al. (2013), KV-SPHFs can be instantiated on Cramer–Shoup ciphertexts, thus yielding very efficient (and pairing free) constructions.

Group key exchange protocols withstanding ephemeral‐key reveals

When a group key exchange protocol is executed, the session key is typically extracted from two types of secrets: long-term keys (for authentication) and freshly generated (often random) values. The leakage of this latter so-called ephemeral keys has been extensively analysed in the 2-party case, yet very few works are concerned with it in the group setting. The authors provide a generic group key exchange construction that is strongly secure, meaning that the attacker is allowed to learn both long-term and ephemeral keys (but not both from the same participant, as this would trivially disclose the session key). Their design can be seen as a compiler, in the sense that it builds on a 2-party key exchange protocol which is strongly secure and transforms it into a strongly secure group key exchange protocol by adding only one extra round of communication. When applied to an existing 2-party protocol from Bergsma et al., the result is a 2-round group key exchange protocol which is strongly secure in the standard model, thus yielding the first construction with this property.

An ECC‐based authenticated group key exchange protocol in IBE framework

SummaryWith the rapid demand for various increasing applications, the internet users require a common secret key to communicate among a group. The traditional key exchange protocols involve a trusted key generation center for generation and distribution of the group key among the various group members. Therefore, the establishment of a trusted key generation center server and the generation (and distribution) of common session key require an extra overhead. To avoid this difficulty, a number of group key exchange protocols have been proposed in the literature. However, these protocols are vulnerable to many attacks and have a high computational and communication cost. In this paper, we present an elliptic curve cryptography–based authenticated group key exchange (ECC‐AGKE) protocol, which provides better security and has lower computational cost compared to related proposed schemes. Further, a complexity reduction method is deployed to reduce the overall complexity of the proposed elliptic curve cryptography–based authenticated group key exchange protocol. The security of proposed work is ensured by the properties of elliptic curves. A security adversarial model is given and an extensive formal security analysis against our claim is done in the random oracle model. We also made a comparison of our proposed protocol with similar works and found that ours have better complexity, security and efficiency over others.

A new strong security model for stateful authenticated group key exchange

Stateful authenticated group key exchange (stAGKE) represents an important class of authenticated group key exchange (AGKE) such as tree-based AGKE. The computation of either ephemeral public key or session key in a new stAGKE session may be based on the ephemeral secret state from some previously established session. We notice that earlier AGKE models may be not able to provide appropriate security arguments for stAGKE. In this work, a new model is proposed for stAGKE to formulate security properties in particular for resistance to the leakage attacks on ephemeral key. To be of independent interest, the new model is also flexible, which can be used for analyzing either stateless or stateful AGKE protocols. We show the validity of our model by introducing a new tree-based protocol construction for stAGKE. The proposed scheme is proven secure in our new proposed model without random oracles.

An active attack on a distributed Group Key Exchange system

In this work, we introduce an active attack on a Group Key Exchange protocol by Burmester and Desmedt. The attacker obtains a copy of the shared key, which is created in a collaborative manner with the legal users in a communication group.