Security is a significant problem for communications in many scenarios in Internet of Things (IoT), such as military applications, electronic payment, wireless reprogramming of smart devices and so on. To protect communications, a secret key shared by the communicating parties is often required. Authenticated key exchange (AKE) is one of the most widely used methods to provide two or more parties communicating over an open network with a shared secret key. It has been studied for many years. A large number of protocols are available by now. The majority of existing AKE protocols require the two communicating parties execute equivalent computational tasks. However, many communications take place between two devices with significantly different computational capabilities, such as a cloud center and a mobile terminal, a gateway and a sensor node, and so on. Most available AKE protocols do not perfectly match these scenarios. To further address the security problem in communications between parties with fairly unbalanced computational capabilities, this thesis studies AKE protocols with unbalanced computational requirements on the communicating parties. We firstly propose a method to unbalance computations in the Elliptic Curve Diffie-Hellman (ECDH) key exchange scheme. The resulting scheme is named as UECDH scheme. The method transfers one scalar multiplication from the computationally limited party to its more powerful communicating partner. It significantly reduces the computational burden on the limited party since scalar multiplication is the most time-consuming operation in the ECDH scheme. When applying the UECDH scheme to design AKE protocols, the biggest challenge is how to achieve authentication. Without authentication, two attacks (the man-in-the-middle attack and the impersonation attack) can be launched to the protocols. To achieve authentication, we introduce different measures that are suitable for a variety of use cases. Based on the authentication measures, we propose four suites of UECDH-based AKE protocols. The security of the protocols is discussed in detail. We also implement prototypes of these protocols and similar protocols in international standards including IEEE 802.15.6, Transport Layer Security (TLS) 1.3 and Bluetooth 5.0. Experiments are carried out to evaluate the performance. The results show that in the same experimental platform, the proposed protocols are more friendly to the party with limited computational capability, and have better performance than similar protocols in these international standards.
Security is a significant problem for communications in many scenarios in Internet of Things (IoT), such as military applications, electronic payment, wireless reprogramming of smart devices and so on. To protect communications, a secret key shared by the communicating parties is often required. Authenticated key exchange (AKE) is one of the most widely used methods to provide two or more parties communicating over an open network with a shared secret key. It has been studied for many years. A large number of protocols are available by now. The majority of existing AKE protocols require the two communicating parties execute equivalent computational tasks. However, many communications take place between two devices with significantly different computational capabilities, such as a cloud center and a mobile terminal, a gateway and a sensor node, and so on. Most available AKE protocols do not perfectly match these scenarios. To further address the security problem in communications between parties with fairly unbalanced computational capabilities, this thesis studies AKE protocols with unbalanced computational requirements on the communicating parties. We firstly propose a method to unbalance computations in the Elliptic Curve Diffie-Hellman (ECDH) key exchange scheme. The resulting scheme is named as UECDH scheme. The method transfers one scalar multiplication from the computationally limited party to its more powerful communicating partner. It significantly reduces the computational burden on the limited party since scalar multiplication is the most time-consuming operation in the ECDH scheme. When applying the UECDH scheme to design AKE protocols, the biggest challenge is how to achieve authentication. Without authentication, two attacks (the man-in-the-middle attack and the impersonation attack) can be launched to the protocols. To achieve authentication, we introduce different measures that are suitable for a variety of use cases. Based on the authentication measures, we propose four suites of UECDH-based AKE protocols. The security of the protocols is discussed in detail. We also implement prototypes of these protocols and similar protocols in international standards including IEEE 802.15.6, Transport Layer Security (TLS) 1.3 and Bluetooth 5.0. Experiments are carried out to evaluate the performance. The results show that in the same experimental platform, the proposed protocols are more friendly to the party with limited computational capability, and have better performance than similar protocols in these international standards.
In disaster scenarios, such as an area after a terrorist attack, security is a significant problem since communications involve information for the rescue officers, such as polices, militaries, emergency medical technicians, and the survivors. Such information is critically important for the rescue organizations; and protecting the privacy of the survivors is required. Normally, authenticated key exchange (AKE) is an underlying approach for security. However, available AKE protocols are either inconvenient or infeasible in disaster areas due to the very nature of disasters. To address the security problem in disaster scenarios, we propose two pairing-free identity-based AKE (ID-AKE) protocols that have unbalanced computational requirements on the two parties. Compared with existing AKE protocols, the proposed protocols have a number of advantages in disaster scenarios: 1) they are more convenient than symmetric cryptography-based AKE protocols since they do not require any preshared secret between the parties; 2) they are more feasible than asymmetric cryptography-based AKE protocols since they do not require any online server; and 3) they are more friendly to battery-powered and computationally limited devices than pairing-based and pairing-free ID-AKE protocols since they do not involve any bilinear pairing (a time-consuming operation), and have lower computational requirement on the limited party. Security of the proposed protocols are analyzed in detail; and prototypes of them are implemented to evaluate the performance. We also illustrate the application of the protocols through a vivid use case in a terrorist attack scenario.
Authenticated key exchange (AKE) protocol for client–server environments is a significant cryptographic primitive that provides communication confidentiality and mutual authentication between clients and servers. In an Internet of Things (IoT) environment, clients typically employ IoT devices with limited computing capability to interact with servers through the Internet. Numerous AKE protocols suitable for IoT devices, called AKE-IoT protocols, have been proposed. Recently, side-channel attacks have been conducted to defeat traditional cryptographic protocols because a side-channel adversary can retrieve partial content of long-term or short-term secret keys. Several leakage-resilient AKE (LRAKE) protocols were presented to counteract such attacks. Unfortunately, the existing LRAKE protocols are not suitable for IoT devices because expensive pairing operations are required for client sides. In this article, we propose the first efficient LRAKE protocol suitable for IoT devices, named LRAKE-IoT. By the unbalanced computation method, no pairing operation is required for client sides in our protocol. In the generic bilinear pairing group model, security analysis is conducted to demonstrate the security of the proposed protocol in the continuous-leakage-resilient extended-Canetti–Krawczyk model. Finally, computational experiences on two IoT devices are given to show that the proposed protocol is well-suited for IoT devices.
An authenticated key exchange for the Internet of Things (IoT) sensor layer is discussed in this paper. This paper presents an enhanced key exchange protocol to provide an authentication scheme and data confidentiality for IoT sensor layer. In our approach, we incorporate an identity-based authentication scheme into the existing key exchange protocol based on Elliptic Curve Diffie Hellman (ECDH). We utilize two communication channels for the process, main channel and auxiliary channel. The main channel is used to exchange key and sensor data and the auxiliary channel is used to exchange the identity information prior to the key exchange process. To provide the data confidentiality, AES encryption algorithm is implemented with a key derived from shared secret key to ensure the Perfect Forward Secrecy. For the evaluations, there are four parameters that are evaluated: the protocol resistance, formal verification of protocol, the protocol security, and performance testing. The protocol resistance was evaluated using security analysis against common security threats on IoT sensor layer. The formal verification of the proposed protocol was evaluated using Scyther, and the protocol security was evaluated using attack scenarios (i.e., authentication and sniffing attack) to prove the authentication and confidentiality. The performance testing was conducted to measure time complexity and memory complexity of the protocol. The experiment results show that the proposed protocol is able to provide an authentication mechanism, data confidentiality, and resilience against common security threats at IoT sensor layers.
With the advancement in Internet-based technologies, network applications are no longer just limited to one-to-one communication; instead, it has become a publicly accessible resource. Regardless of this growth, such applications bring specific challenges concerning authentication, integrity, and privacy. Cryptography stands as an ideal solution to overcome these issues through an interactive method of secure communication called Key Exchange. Key exchange protocols allow two or more entities to agree upon a shared secret transmitted over a public channel without revealing any information to an eavesdropper.
This thesis contributes to the design and analysis of the variants of key exchange protocols along with their applications. As per the security requirements, the proposed schemes are either designed in an interactive model or a non-interactive model. Each scheme undergoes a series of formal and informal security analysis. The formal analysis provides simulation result using cryptographic models. Whereas, an informal analysis showcases the theoretical proves on known attacks where an adversary controls the network. The performance analysis maps the protocol’s efficiency based on the computation cost and communication size.
The first contribution introduces an interactive two-party authenticated key exchange protocol. We begin by investigating the security flaws in an existing system such as, lack of user anonymity, trace attack, clogging attack, and failure to resist replay attack. Then proposed an authenticated self-certified key exchange protocol that overcomes the addressed issues. Also, it eliminates the requirements of a trusted certificate authority to authorize the entities. The scheme achieves anonymity during session execution, mutual authentication and enables session key agreement.Based on the ideology, an application is designed, forsecure communication between ad-hoc nodes in a mobile ad-hoc network.
The second contribution contributes to the design of an Identity-based authenticated three-party key exchange protocol that overcomes the incapability of managing huge
peer-to-peer communication and high computation cost faced by two-party authenticated key exchange protocols. The proposed scheme preserves user privacy by enabling the property of anonymity and ensures non-repudiation. Based on the ideology, an application is designed to establish a secure session key between two users with the help of a trusted server for an electronic payment system.
The third contribution proposes an interactive pairing-free certificateless authenticated group key agreement scheme suitable for a resource constrained mobile network. The scheme allows any user to join or leave the group dynamically. The key agreement protocol devised in this scheme ensures un-deniability property by incorporating the signcryption, and unsigncryption algorithm.
The final contribution presents a non-interactive Identity-based deniable authentication protocol that allows an intended receiver to identify the origin of a given message without being able to prove sender’s identity to a third party.
With the rise of the Internet of Things (IoT), maintaining data confidentiality and protecting user privacy have become increasingly challenging. End devices in the IoT are often deployed in unattended environments and connected to open networks, making them vulnerable to physical tampering and other security attacks. Different authentication key agreement (AKA) schemes have been used in practice; several of them do not cover the necessary security features or are incompatible with resource-constrained end devices. Their security proofs have been performed under the Random-Oracle model. We present an AKA protocol for end devices and servers. The proposal leverages the ECC-based key exchange mechanism and one-way hash function-based message authentication method to achieve mutual authentication, user anonymity, and forward security. A formal security proof of the proposed scheme is performed under the standard model and the eCK model with the elliptic curve encryption computational assumptions, and formal verification is performed with ProVerif. According to the performance comparison, it is revealed that the proposed scheme offers user anonymity, perfect forward security, and mutual authentication, and resists typical attacks such as ephemeral secret leakage attacks, impersonation attacks, man-in-the-middle attacks, and key compromise impersonation attacks. Moreover, the proposed scheme has the lowest computational and communication overhead compared to existing schemes.
A two-party authenticated key exchange (AKE) protocol allows each of the two parties to share a common secret key over insecure channels, even in the presence of active adversaries who can actively control and modify the exchanged messages. To capture the malicious behaviors of the adversaries, there have been many efforts to define security models. Amongst them, the extended Canetti–Krawczyk (eCK) security model is considered one of the strongest security models and has been widely adopted. In this paper, we present a simple construction of a pairing-based eCK-secure AKE protocol in the standard model. Our protocol can be instantiated with a suitable signature scheme (i.e., an existentially unforgeable signature scheme against adaptive chosen message attacks). The underlying assumptions of our construction are the decisional bilinear Diffie–Hellman assumption and the existence of a pseudorandom function. Note that the previous eCK-secure protocol constructions either relied on random oracles for their security or used somewhat strong assumptions, such as the existence of strong-pseudorandom functions, target collision-resistant functions, etc., while our protocol construction uses fewer and more-standard assumptions in the standard model. Furthermore, preserving the same security argument, our protocol can be instantiated with any appropriate signature scheme that comes in the future with better efficiency.