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.
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.
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.
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 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.
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 proliferation of Internet of Things (IoT) devices that use the Message Queuing Telemetry Transport (MQTT) protocol poses significant security challenges in the emerging quantum computing era. Current Transport Layer Security (TLS) implementations rely on classical cryptographic algorithms vulnerable to Shor's algorithm. This paper proposes PQ-MQTT, a hybrid post-quantum secure communication protocol that integrates ML-KEM-768 with X25519 for key encapsulation and a lightweight session-key derivation mechanism optimized for resource-constrained IoT publishers. We present a formal security analysis under the Quantum Random Oracle Model (QROM), demonstrating resilience against store-now-decryptlater attacks. Experimental evaluation on the Raspberry Pi 4, ESP32, and Arduino Nano 33 platforms shows that PQ-MQTT achieves handshake latencies of127.3ms,412.7ms, and1,847.2ms, respectively, with 18.2 KB of additional memory overhead. A comparative analysis of pure post-quantum and classical TLS implementations shows energy reductions of23.5%−40.5%relative to pure PQC, achieved through our hybrid optimization approach, while maintaining 94.2 % throughput efficiency.
The growth of quantum computing reveals a series of significant threats to cryptographic systems known today, such as RSA, ECC, and Diffie-Hellman, which are extremely important for Internet security, but are threatened by the increase in possible quantum attacks. The area of public and private key cryptography is vast. Therefore, this article addresses post-quantum cryptography (PQC) algorithms and the challenges of implementing them in Internet of Things (IoT) devices, given the difficulty of application due to restricted resources, such as RAM and clock speed . To this end, we will discuss the need for standardization of algorithms considering low-resource IoT devices, prioritizing RAM over ROM, meeting the needs of low-memory devices, which are lighter. The National Institute of Standards and Technology (NIST) has validated four cryptographic systems that are secure against quantum attacks. We analyze the implications of these systems on the infrastructure of current networks and will compare in detail these algorithms and their respective strengths, weaknesses, and trade-offs. We evaluate the feasibility of post-quantum encryption (PQC) algorithms in resource-constrained IoT devices using the ESP-WROOM-32 microcontroller. Three cryptographic schemes were implemented and compared.