A New Family of Implicitly Authenticated Diffie-Hellman Protocols

Cryptography algorithm standards play a key role both to the practice of information security and to cryptography theory research. Among them, the MQV and HMQV protocols ((H)MQV, in short) are a family of implicitly authenticated Diffie-Hellman key-exchange (DHKE) protocols that are among the most efficient and are widely standardized. In this work, from some new perspectives and under some new design rationales, and also inspired by the security analysis of HMQV, we develop a new family of practical implicitly authenticated DHKE (IA-DHKE) protocols, which enjoy notable performance among security, efficiency, privacy, fairness and easy deployment. We make detailed comparisons between our new protocols and (H)MQV, showing that the newly developed protocols outperform HMQV in most aspects. Very briefly speaking, we achieve: 1. The most efficient provably secure IA-DHKE protocol to date, and the first online-optimal provably secure IA-DHKE protocols. 2. The first IA-DHKE protocol that is provably secure, resilience to the leakage of DH components and exponents, under merely standard assumptions without additionally relying on the knowledge-of-exponent assumption (KEA). 3. The first provably secure privacy-preserving and computationally fair IA-DHKE protocol, with privacy-preserving properties of reasonable deniability and post-ID computability and the property of session-key computational fairness. Guided by our new design rationales, in this work we also formalize and introduce some new concept, say session-key computational fairness (as a complement to session-key security), to the literature

Cryptographic Protocols, Sensor Network Key Management, and RFID Authentication

This thesis includes my research on efficient cryptographic protocols, sensor network key management, and radio frequency identification (RFID) authentication protocols. Key exchange, identification, and public key encryption are among the fundamental protocols studied in cryptography. There are two important requirements for these protocols: efficiency and security. Efficiency is evaluated using the computational overhead to execute a protocol. In modern cryptography, one way to ensure the security of a protocol is by means of provable security. Provable security consists of a security model that specifies the capabilities and the goals of an adversary against the protocol, one or more cryptographic assumptions, and a reduction showing that breaking the protocol within the security model leads to breaking the assumptions. Often, efficiency and provable security are not easy to achieve simultaneously. The design of efficient protocols in a strict security model with a tight reduction is challenging. Security requirements raised by emerging applications bring up new research challenges in cryptography. One such application is pervasive communication and computation systems, including sensor networks and radio frequency identification (RFID) systems. Specifically, sensor network key management and RFID authentication protocols have drawn much attention in recent years. In the cryptographic protocol part, we study identification protocols, key exchange protocols, and ElGamal encryption and its variant. A formal security model for challenge-response identification protocols is proposed, and a simple identification protocol is proposed and proved secure in this model. Two authenticated key exchange (AKE) protocols are proposed and proved secure in the extended Canetti-Krawczyk (eCK) model. The proposed AKE protocols achieve tight security reduction and efficient computation. We also study the security of ElGamal encryption and its variant, Damgard’s ElGamal encryption (DEG). Key management is the cornerstone of the security of sensor networks. A commonly recommended key establishment mechanism is based on key predistribution schemes (KPS). Several KPSs have been proposed in the literature. A KPS installs pre-assigned keys to sensor nodes so that two nodes can communicate securely if they share a key. Multi-path key establishment (MPKE) is one component of KPS which enables two nodes without a shared key to establish a key via multiple node-disjoint paths in the network. In this thesis, methods to compute the k-connectivity property of several representative key predistribution schemes are developed. A security model for MPKE and efficient and secure MPKE schemes are proposed. Scalable, privacy-preserving, and efficient authentication protocols are essential for the success of RFID systems. Two such protocols are proposed in this thesis. One protocol uses finite field polynomial operations to solve the scalability challenge. Its security is based on the hardness of the polynomial reconstruction problem. The other protocol improves a randomized Rabin encryption based RFID authentication protocol. It reduces the hardware cost of an RFID tag by using a residue number system in the computation, and it provides provable security by using secure padding schemes

Cryptographic Schemes based on Elliptic Curve Pairings

This thesis introduces the concept of certificateless public key cryptography (CLPKC). Elliptic curve pairings are then used to make concrete CL-PKC schemes and are also used to make other efficient key agreement protocols. CL-PKC can be viewed as a model for the use of public key cryptography that is intermediate between traditional certificated PKC and ID-PKC. This is because, in contrast to traditional public key cryptographic systems, CL-PKC does not require the use of certificates to guarantee the authenticity of public keys. It does rely on the use of a trusted authority (TA) who is in possession of a master key. In this respect, CL-PKC is similar to identity-based public key cryptography (ID-PKC). On the other hand, CL-PKC does not suffer from the key escrow property that is inherent in ID-PKC. Applications for the new infrastructure are discussed. We exemplify how CL-PKC schemes can be constructed by constructing several certificateless public key encryption schemes and modifying other existing ID based schemes. The lack of certificates and the desire to prove the schemes secure in the presence of an adversary who has access to the master key or has the ability to replace public keys, requires the careful development of new security models. We prove that some of our schemes are secure, provided that the Bilinear Diffie-Hellman Problem is hard. We then examine Joux’s protocol, which is a one round, tripartite key agreement protocol that is more bandwidth-efficient than any previous three-party key agreement protocol, however, Joux’s protocol is insecure, suffering from a simple man-in-the-middle attack. We show how to make Joux’s protocol secure, presenting several tripartite, authenticated key agreement protocols that still require only one round of communication. The security properties of the new protocols are studied. Applications for the protocols are also discussed

Identity-Concealed Authenticated Encryption and Key Exchange

Identity concealment and zero-round trip time (0-RTT) connection are two of current research focuses in the design and analysis of secure transport protocols, like TLS1.3 and Google\u27s QUIC, in the client-server setting. In this work, we introduce a new primitive for identity-concealed authenticated encryption in the public-key setting, referred to as {higncryption, which can be viewed as a novel monolithic integration of public-key encryption, digital signature, and identity concealment. We present the security definitional framework for higncryption, and a conceptually simple (yet carefully designed) protocol construction. As a new primitive, higncryption can have many applications. In this work, we focus on its applications to 0-RTT authentication, showing higncryption is well suitable to and compatible with QUIC and OPTLS, and on its applications to identity-concealed authenticated key exchange (CAKE) and unilateral CAKE (UCAKE). In particular, we make a systematic study on applying and incorporating higncryption to TLS. Of independent interest is a new concise security definitional framework for CAKE and UCAKE proposed in this work, which unifies the traditional BR and (post-ID) frameworks, enjoys composability, and ensures very strong security guarantee. Along the way, we make a systematically comparative study with related protocols and mechanisms including Zheng\u27s signcryption, one-pass HMQV, QUIC, TLS1.3 and OPTLS, most of which are widely standardized or in use

Critical Perspectives on Provable Security: Fifteen Years of Another Look Papers

We give an overview of our critiques of “proofs” of security and a guide to our papers on the subject that have appeared over the past decade and a half. We also provide numerous additional examples and a few updates and errata

Physical Layer Group Key Agreement for Automotive Controller Area Networks

Distribution of cryptographic keys between devices communicating over a publicly accessible medium is an important component of secure design for networked systems. In this paper, we consider the problem of group key exchange between Electronic Control Units (ECUs) connected to the Controller Area Network (CAN) within an automobile. Typically, existing solutions map schemes defined for traditional network systems to the CAN. Our contribution is to utilize physical properties of the CAN bus to generate group keys. We demonstrate that pairwise interaction between ECUs over the CAN bus can be used to efficiently derive group keys in both authenticated and non-authenticated scenarios. We illustrate the efficiency and security properties of the proposed protocols. The scalability and security properties of our scheme are similar to multi-party extensions of Diffie-Hellman protocol, without the computational overhead of group operations

A Security Analysis of Some Physical Content Distribution Systems

Content distribution systems are essentially content protection systems that protect premium multimedia content from being illegally distributed. Physical content distribution systems form a subset of content distribution systems with which the content is distributed via physical media such as CDs, Blu-ray discs, etc. This thesis studies physical content distribution systems. Specifically, we concentrate our study on the design and analysis of three key components of the system: broadcast encryption for stateless receivers, mutual authentication with key agreement, and traitor tracing. The context in which we study these components is the Advanced Access Content System (AACS). We identify weaknesses present in AACS, and we also propose improvements to make the original system more secure, flexible and efficient

A security architecture for IPv6 enabled wireless medical sensor networks.

We present the design of an IPv6 enabled wireless sensor network based on the IEEE 802.15.4 standard for medical monitoring. We design a routing mechanism for efficient flooding, a hop-by-hop error recovery and congestion control mechanism for reliable packet delivery and a lightweight security architecture for the medical monitoring system. We extend the widely used Extensible Authentication Protocol (EAP) to employ the Generalized Pre-shared Key (GPSK) authentication method with some optimizations for securing the system. We use the 3-party EAP model with the Personal Area Network Coordinator (PAN coordinator) of IEEE 802.15.4 standard as the EAP authenticator for authenticating sensor nodes within the radio range of the PAN coordinator. In order to use EAP authentication for a sensor node several hops away from the PAN coordinator, we define a new role (relay authenticator) for its coordinator which tunnels EAP messages to the PAN coordinator securely. We define EAP message encapsulation for IEEE 802.15.4 networks and a key hierarchy for the security architecture. We have simulated the system and shown that EAP based authentication is feasible in wireless sensor networks.The original print copy of this thesis may be available here: http://wizard.unbc.ca/record=b136235