The advent of quantum computing poses significant threats to classical public-key cryptographic systems such as RSA and Elliptic Curve Cryptography, necessitating quantum-safe migration paths for Internet of Things (IoT) communication. The Ephemeral Diffie-Hellman Over COSE (EDHOC) protocol provides lightweight authenticated key exchange for resource-constrained IoT devices but lacks quantum-safe security and formally verified implementations. This thesis introduces KEMEDHOC, a KEM-based, signature-free, post-quantum variant of EDHOC that achieves mutual authentication through optimized integration of Key Encapsulation Mechanisms (KEMs). Compared to the direct adaptation, KEMEDHOC reduces noticeably message size (by over \textbf{33\%}) and handshake time (by \textbf{15\%}), while maintaining comparable security levels. Formal verification, at design-level, using ProVerif confirms that KEMEDHOC preserve all core EDHOC security properties, including mutual authentication, confidentiality, and forward secrecy. Verified implementations (EDHOC* and KEMEDHOC*) developed in F* and Low* ensure functional correctness, memory safety, and timing constant-time behavior, down to verified C code through KaRaMel compiler. Overall, this thesis delivers the first end-to-end formally verified post-quantum variant of EDHOC, demonstrating that formal assurance and post-quantum security can be obtained efficiently in lightweight key exchange protocols.
The advent of quantum computing poses significant threats to classical public-key cryptographic systems such as RSA and Elliptic Curve Cryptography, necessitating quantum-safe migration paths for Internet of Things (IoT) communication. The Ephemeral Diffie-Hellman Over COSE (EDHOC) protocol provides lightweight authenticated key exchange for resource-constrained IoT devices but lacks quantum-safe security and formally verified implementations. This thesis introduces KEMEDHOC, a KEM-based, signature-free, post-quantum variant of EDHOC that achieves mutual authentication through optimized integration of Key Encapsulation Mechanisms (KEMs). Compared to the direct adaptation, KEMEDHOC reduces noticeably message size (by over \textbf{33%}) and handshake time (by \textbf{15%}), while maintaining comparable security levels. Formal verification, at design-level, using ProVerif confirms that KEMEDHOC preserve all core EDHOC security properties, including mutual authentication, confidentiality, and forward secrecy. Verified implementations (EDHOC* and KEMEDHOC*) developed in F* and Low* ensure functional correctness, memory safety, and timing constant-time behavior, down to verified C code through KaRaMel compiler. Overall, this thesis delivers the first end-to-end formally verified post-quantum variant of EDHOC, demonstrating that formal assurance and post-quantum security can be obtained efficiently in lightweight key exchange protocols.
Several lightweight protocols are being developed to secure communication in resource-constrained environments. Ephemeral Diffie-Hellman over COSE (EDHOC) plays a key role in this lightweight protocol family by managing the key establishment process. However, due to the vulnerability of the discrete logarithm problem to Shor’s algorithm, a quantum-resistant replacement for Diffie-Hellman is required. This work examines the quantum-resistant transition of EDHOC, focusing on its multiple authentication methods as a step toward enabling robust post-quantum security for IoT devices. A novel authentication method for EDHOC is introduced, utilizing Key Encapsulation Mechanisms (KEMs) as a replacement for the static Diffie-Hellman (DH) authentication method, providing a post-quantum signature-free alternative. Among existing post-quantum algorithms for both KEMs and signatures, the NIST-standardized ML-KEM offers the fastest implementation at the lowest memory cost, both of which are crucial for resource-constrained devices. While compatible with various post-quantum KEMs, the method can exploit the computational efficiency of ML-KEM to bring a PQ Signature-free EDHOC to highly constrained devices, providing the same security guarantees as classical EDHOC once the handshake is complete. Additionally, an efficient three-message handshake KEM-based EDHOC Initiator Known Responder (IKR) variant is proposed for environments with pre-established peer awareness.
The Ephemeral Diffie-Hellman over COSE (EDHOC) is a compact and lightweight key establishment protocol for constrained scenarios that provides end-to-end application layer security context. However, because of the vulnerability of the discrete logarithm problem to Shor’s algorithm, a quantum resistant replacement for Diffie-Hellman is required. This paper proposes an architecture to transform EDHOC into a quantum-resistant protocol, with an open-source implementation supporting various Post Quantum Cryptography (PQC) schemes from the National Institute of Standards and Technology (NIST) PQC standardization process. Necessary modifications to EDHOC are analyzed, integrating PQC Key Encapsulation Mechanisms (KEMs) and PQC digital signatures in a complete Post-Quantum (PQ) version of the EDHOC protocol (PQ-EDHOC). PQC operations often involve complex computations and require larger byte sizes, which can challenge resource-constrained devices designed for lightweight operation in constrained network environments. To evaluate the applicability of various PQC schemes in a realistic PQ EDHOC environment, various PQC KEM and Digital Signature combinations are assessed for execution time, energy consumption, memory usage, and network performance on an nRF52840 ARM Cortex-M4 platform with a 6LoWPAN (IPv6 over Low-Power Wireless Personal Area Networks) over BLE (Bluetooth LowEnergy) network. Results indicate that NIST standardized ML-KEM emerges as the only suitable KEM choice for resource-constrained environments, while promising new signature schemes, like HAWK, show significant performance improvement over the NIST standardized ML-DSA and selected for standardization FALCON.
Transport Layer Security (TLS) is considered to be the most used standard security protocol for the Internet of Things (IoT). However, as TLS was originally designed for computer networks, it is not optimal with respect to efficiency. Therefore, a new protocol called Object Security for Constrained RESTful Environments (OSCORE) has been standardized for securing constrained devices. Currently, the Ephemeral-Diffie-Hellman-Over-COSE (EDHOC) protocol, which is a key exchange protocol to define a session key used in OSCORE, is also in the process of being standardized. EDHOC consists of four authentication modes, each offering different security strengths and performance. However, these modes are not yet secure against quantum attacks. Since we are in a transition period and do not yet possess deeply analyzed post-quantum algorithms, we propose a generic hybrid protocol. As such, the protocol can easily update from one post-quantum algorithm to the other and becomes secure against either a post-quantum attack or a potential attack against a newly defined post-quantum algorithm. The proposed mode does not require any changes to the original EDHOC protocol and offers perfect backward compatibility. The security is ensured using Real-Or-Random (ROR) logic, and additional performance costs are analyzed using different variants of post-quantum algorithms.
Quantum computing poses a significant threat to Wireless Sensor Networks (WSNs) by undermining traditional cryptographic algorithms such as RSA and Elliptic Curve Cryptography (ECC). This work proposes a quantum-safe architecture for WSNs that integrates post-quantum cryptography (PQC) with lightweight IoT protocols to ensure long-term confidentiality, authenticity, and resilience. The framework leverages ML-KEM for key encapsulation and ML-DSA/SLH-DSA for signatures, and seamlessly integrates with EDHOC, OSCORE, and COSE. A novel Efficient Adaptive Parameter Selection (EAPS) mechanism dynamically adjusts cryptographic strength to balance security, energy consumption, and latency under varying network conditions. Experimental evaluation demonstrates that ciphertext fragmentation (8–27 pieces) results in manageable completion times of 4–10 seconds, while join operations consume only 0.005–0.03 J per cryptographic handshake event, while system-level energy consumption including network overhead is higher (~1.0–1.4 J per join cycle depending on hop count and retransmissions). Battery lifetime projections under steady-state sensing workloads range from approximately 115–280 months for low-duty-cycle operation, whereas realistic deployment conditions with periodic communication yield effective lifetimes of 11.5–24 months. Security analysis confirms robust resistance against downgrade attacks and Harvest-Now-Decrypt-Later (HNDL) threats. Moreover, EAPS reduces risk scores by over 50% compared to fixed schemes with less than 10% additional energy overhead, and batch signature verification improves scalability by increasing throughput from ~1,600 to ~2,800 verifications per second. Overall, the proposed framework demonstrates that WSNs can achieve quantum-resistant security with minimal performance trade-offs, ensuring readiness for the post-quantum era.
Traditional public-key cryptography algorithms, such as Elliptic Curve Diffie-Hellman (ECDH), are vulnerable to quantum computing attacks. More critically, security protocols based on these algorithms are exposed to the “Harvest Now, Decrypt Later” threat, an ongoing risk that emphasizes the urgency of transitioning to post-quantum cryptography. This transition presents a significant challenge for lightweight security protocols, such as Ephemeral Diffie-Hellman over COSE (EDHOC), which are designed for IoT environments. To address this, a PQ/T hybrid key exchange construction for EDHOC is proposed, combining post-quantum mechanisms alongside traditional algorithms to mitigate future quantum threats while remaining secure against current threats using well-established classical cryptography. The scheme is evaluated on a CortexM4 processor, demonstrating the best performance with ML-KEM-512, with a slight increase in processing time, limited RAM overhead, and a roughly sevenfold increase in message size. Despite these trade-offs, the hybrid construction remains practical and represents a viable option for enhancing EDHOC security in anticipation of the post-quantum era in constrained environments.
The rapid proliferation of Internet of Things (IoT) devices has revolutionized digital communication, yet it simultaneously poses unprecedented security challenges due to constrained device capabilities and increasing cyber threats. Conventional cryptographic techniques, while currently effective, are vulnerable to emerging quantum computing technologies that threaten to render classical encryption obsolete. This paper explores the integration of quantum-safe cryptographic techniques within IoT networks to ensure long-term confidentiality, integrity, and authentication. It examines post-quantum cryptographic primitives, including lattice-based, hash-based, multivariate, and code-based schemes, and evaluates their suitability for resource-constrained IoT environments. The study focuses on lightweight implementation strategies, balancing computational efficiency with robust security requirements. Simulation analyses demonstrate that properly optimized quantum safe protocols can provide resilient encryption, key exchange, and digital signature functionalities without overwhelming device resources. Furthermore, the integration of these techniques with IoT communication standards and secure network protocols ensures end-to-end protection across heterogeneous networks. Challenges such as latency, energy consumption, and scalability are addressed, highlighting the necessity of tailored cryptographic solutions for diverse IoT applications. The findings confirm that quantum safe cryptography is essential for future-proofing IoT networks, offering sustainable security measures that remain resilient against both classical and quantum adversaries, thereby supporting the continued expansion of secure and intelligent interconnected systems.