Integrating post-quantum cryptography (NTRU) in the TLS protocol

Dissertação de mestrado em Computer ScienceWe aim to integrate new “suites”, using post-quantum authentication and encryption tech niques, in the TLS protocol. Namely, this project is dedicated to integrating algorithms belonging to the NTRU family of cryptossystems in the OpenSSL library and in the Python package “Cryptography”. Even though all the algorithms included in this project have already been imple mented as part of their submissions to the NIST Post-Quantum Standartization project, currently there doesn’t seem to exist a way to perform prototyping and testing of these cryp tossystems in real-life use cases, and it would be interesting to create such tools. We also aim to test if these algorithms could be further optimized for speed and efficiency by comparing the reference implementations (submited to NIST and publicly avail able) with our own implementations that perform some required mathematical operations in a very efficient manner (by using specialized number theory libraries).Pretende-se integrar novas “suites” no protocolo TLS que usem técnicas de autenticação e cifra na categoria de técnicas pós-quanticas. Nomeadamente, este projecto é dedicado à integração de algoritmos da família NTRU na biblioteca OPENSSL e na “package” Cryptography para o Python. Apesar de todos os algoritmos contemplados neste projeto já terem sido implementa dos no âmbito da sua submissão ao NIST Post-Quantum Standartization project, actualmente não parece existir forma de testar e prototipar estes criptossistemas em casos de uso realistas, e seria interessante desenvolver ferramentas que o permitam. Pretende-se também aferir se estes algoritmos podem ser optimizados em eficiência e velocidade de execução, comparando as implementações de referência (submetidas ao NIST e disponiveis publicamente) com as nossas implementações, que efectuam algumas operações matemáticas necessárias de forma muito eficiente (com recusro a bibliotecas de teoria de números especializadas)

Post-quantum blockchain for internet of things domain

This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University LondonIn the evolving realm of quantum computing, emerging advancements reveal substantial challenges and threats to existing cryptographic infrastructures, particularly impacting blockchain technologies. These are pivotal for securing the Internet of Things (IoT) ecosystems. The traditional blockchain structures, integral to myriad IoT applications, are susceptible to potential quantum computations, emphasizing an urgent need for innovations in post-quantum blockchain solutions to reinforce security in the expansive domain of IoT. This PhD thesis delves into the crucial exploration and meticulous examination of the development and implementation of post-quantum blockchain within the IoT landscape, focusing on the incorporation of advanced post-quantum cryptographic algorithms in Hyperledger Fabric, a forefront blockchain platform renowned for its versatility and robustness. The primary aim is to discern viable post-quantum cryptographic solutions capable of fortifying blockchain systems against impending quantum threats enhancing security and reliability in IoT applications. The research comprehensively evaluates various post-quantum public-key generation and digital signature algorithms, performing detailed analyses of their computational time and memory usage to identify optimal candidates. Furthermore, the thesis proposes an innovative lattice-based digital signature scheme Fast-Fourier Lattice-based Compact Signature over NTRU (Falcon), which leverages the Monte Carlo Markov Chain (MCMC) algorithm as a trapdoor sampler to augment its security attributes. The research introduces a post-quantum version of the Hyperledger Fabric blockchain that integrates post-quantum signatures. The system utilizes the Open Quantum Safe (OQS) library, rigorously tested against NIST round 3 candidates for optimal performance. The study highlights the capability to manage IoT data securely on the post-quantum Hyperledger Fabric blockchain through the Message Queue Telemetry Transport (MQTT) protocol. Such a configuration ensures safe data transfer from IoT sensors directly to the blockchain nodes, securing the processing and recording of sensor data within the node ledger. The research addresses the multifaceted challenges of quantum computing advancements and significantly contributes to establishing secure, efficient, and resilient post-quantum blockchain infrastructures tailored explicitly for the IoT domain. These findings are instrumental in elevating the security paradigms of IoT systems against quantum vulnerabilities and catalysing innovations in post-quantum cryptography and blockchain technologies. Furthermore, this thesis introduces strategies for the optimization of performance and scalability of post-quantum blockchain solutions and explores alternative, energy-efficient consensus mechanisms such as the Raft and Stellar Consensus Protocol (SCP), providing sustainable alternatives to the conventional Proof-of-Work (PoW) approach. A critical insight emphasized throughout this thesis is the imperative of synergistic collaboration among academia, industry, and regulatory bodies. This collaboration is pivotal to expedite the adoption and standardization of post-quantum blockchain solutions, fostering the development of interoperable and standardized technologies enriched with robust security and privacy frameworks for end users. In conclusion, this thesis furnishes profound insights and substantial contributions to implementing post-quantum blockchain in the IoT domain. It delineates original contributions to the knowledge and practices in the field, offering practical solutions and advancing the state-of-the-art in post-quantum cryptography and blockchain research, thereby paving the way for a secure and resilient future for interconnected IoT systems

qSCMS: Post-quantum certificate provisioning process for V2X

Security and privacy are paramount in the field of intelligent transportation systems (ITS). This motivates many proposals aiming to create a Vehicular Public Key Infrastructure (VPKI) for managing vehicles’ certificates. Among them, the Security Credential Management System (SCMS) is one of the leading contenders for standardization in the US. SCMS provides a wide array security features, which include (but are not limited to) data authentication, vehicle privacy and revocation of misbehaving vehicles. In addition, the key provisioning process in SCMS is realized via the so-called butterfly key expansion, which issues arbitrarily large batches of pseudonym certificates in response to a single client request. Although promising, this process is based on classical elliptic curve cryptography (ECC), which is known to be susceptible to quantum attacks. Aiming to address this issue, in this work we propose a post-quantum butterfly key expansion process. The proposed protocol relies on lattice-based cryptography, which leads to competitive key, ciphertext and signature sizes. Moreover, it provides low bandwidth utilization when compared with other lattice-based schemes, and, like the original SCMS, addresses the security and functionality requirements of vehicular communication

Zero-Knowledge Arguments for Matrix-Vector Relations and Lattice-Based Group Encryption

International audienceGroup encryption (GE) is the natural encryption analogue of group signatures in that it allows verifiably encrypting messages for some anonymous member of a group while providing evidence that the receiver is a properly certified group member. Should the need arise, an opening authority is capable of identifying the receiver of any ciphertext. As introduced by Kiayias, Tsiounis and Yung (Asiacrypt'07), GE is motivated by applications in the context of oblivious retriever storage systems, anonymous third parties and hierarchical group signatures. This paper provides the first realization of group encryption under lattice assumptions. Our construction is proved secure in the standard model (assuming interaction in the proving phase) under the Learning-With-Errors (LWE) and Short-Integer-Solution (SIS) assumptions. As a crucial component of our system, we describe a new zero-knowledge argument system allowing to demonstrate that a given ciphertext is a valid encryption under some hidden but certified public key, which incurs to prove quadratic statements about LWE relations. Specifically, our protocol allows arguing knowledge of witnesses consisting of X ∈ Z m×n q , s ∈ Z n q and a small-norm e ∈ Z m which underlie a public vector b = X · s + e ∈ Z m q while simultaneously proving that the matrix X ∈ Z m×n q has been correctly certified. We believe our proof system to be useful in other applications involving zero-knowledge proofs in the lattice setting

Still Wrong Use of Pairings in Cryptography

Several pairing-based cryptographic protocols are recently proposed with a wide variety of new novel applications including the ones in emerging technologies like cloud computing, internet of things (IoT), e-health systems and wearable technologies. There have been however a wide range of incorrect use of these primitives. The paper of Galbraith, Paterson, and Smart (2006) pointed out most of the issues related to the incorrect use of pairing-based cryptography. However, we noticed that some recently proposed applications still do not use these primitives correctly. This leads to unrealizable, insecure or too inefficient designs of pairing-based protocols. We observed that one reason is not being aware of the recent advancements on solving the discrete logarithm problems in some groups. The main purpose of this article is to give an understandable, informative, and the most up-to-date criteria for the correct use of pairing-based cryptography. We thereby deliberately avoid most of the technical details and rather give special emphasis on the importance of the correct use of bilinear maps by realizing secure cryptographic protocols. We list a collection of some recent papers having wrong security assumptions or realizability/efficiency issues. Finally, we give a compact and an up-to-date recipe of the correct use of pairings.Comment: 25 page

Efficient Dynamic Group Signature Scheme with Verifier Local Revocation and Time-Bound Keys using Lattices

Revocation is an important feature of group signature schemes. Verifier Local Revocation (VLR) is a popular revocation mechanism which involves only verifiers in the revocation process. In VLR, a revocation list is maintained to store the information about revoked users. The verification cost of VLR based schemes islinearly proportional to the size of recvocation list. In many applications, the size of revocation list grows with time, which makes the verification process expensive. In this paper, we propose a lattice based dynamic group signature using VLR and time bound keys to reduce the size of revocation list to speed up the verification process. In the proposed scheme, an expiration date is fixed for signing key of each group member, and verifiers can find out (at constantcost) if a signature is generated using an expired key. Hence revocation information of members who are revoked before signing key expiry date (premature revocation) are kept in revocation list, and other members are part of natural revocation. This leads to a significant saving on the revocation check by assuming natural revocation accounts for large fraction of the total revocation. This scheme also takes care of non-forgeability of signing key expiry date