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1. Trustworthy and Efficient Digital Twins in Post-Quantum Era with Hybrid Hardware-Assisted Signatures

   https://doi.org/10.1145/3638250  

   Nouma, Saif E.; Yavuz, Attila A. (December 2023, ACM Transactions on Multimedia Computing, Communications, and Applications)

   Digital Twins (DT) virtually model cyber-physical objects via sensory inputs by simulating or monitoring their behavior. Therefore, DTs usually harbor vast quantities of Internet of Things (IoT) components (e.g., sensors) that gather, process, and offload sensitive information (e.g., healthcare) to the cloud. It is imperative to ensure the trustworthiness of such sensitive information with long-term and compromise-resilient security guarantees. Digital signatures provide scalable authentication and integrity with non-repudiation and are vital tools for DTs. Post-quantum cryptography (PQC) and forward-secure signatures are two fundamental tools to offer long-term security and breach resiliency. However, NIST-PQC signature standards are exorbitantly costly for embedded DT components and are infeasible when forward-security is also considered. Moreover, NIST-PQC signatures do not admit aggregation, which is a highly desirable feature to mitigate the heavy storage and transmission burden in DTs. Finally, NIST recommends hybrid PQ solutions to enable cryptographic agility and transitional security. Yet, there is a significant gap in the state of the art in the achievement of all these advanced features simultaneously. Therefore, there is a significant need for lightweight digital signatures that offer compromise resiliency and compactness while permitting transitional security into the PQ era for DTs. We create a series of highly lightweight digital signatures called Hardware-ASisted Efficient Signature (HASES) that meets the above requirements. The core ofHASES is a hardware-assisted cryptographic commitment construct oracle (CCO) that permits verifiers to obtain expensive commitments without signer interaction. We created threeHASES schemes:PQ-HASES is a forward-secure PQ signature,LA-HASES is an efficient aggregate Elliptic-Curve signature, andHY-HASES is a novel hybrid scheme that combinesPQ-HASES andLA-HASES with novel strong nesting and sequential aggregation.HASES does not require a secure-hardware on the signer. We prove thatHASES schemes are secure and implemented them on commodity hardware and and 8-bit AVR ATmega2560. Our experiments confirm thatPQ-HASES andLA-HASES are two magnitudes of times more signer efficient than their PQ and conventional-secure counterparts, respectively.HY-HASES outperforms NIST PQC and conventional signature combinations, offering a standard-compliant transitional solution for emerging DTs. We open-sourceHASES schemes for public-testing and adaptation. 

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2. LiteQSign: Lightweight and Quantum-Safe Signatures for Heterogeneous IoT Applications

   https://doi.org/10.1109/ACCESS.2025.3612735  

   Yavuz, Attila Altay; Darzi, Saleh; Nouma, Saif Eddine (October 2025, IEEE Access)

   The rapid proliferation of resource-constrained IoT devices across sectors like healthcare, industrial automation, and finance introduces major security challenges. Traditional digital signatures, though foundational for authentication, are often infeasible for low-end devices with limited computational, memory, and energy resources. Also, the rise of quantum computing necessitates post-quantum (PQ) secure alternatives. However, NIST-standardized PQ signatures impose substantial overhead, limiting their practicality in energy-sensitive applications such as wearables, where signer-side efficiency is critical. To address these challenges, we present LightQSign (LiteQS), a novel lightweight PQ signature that achieves near-optimal signature generation efficiency with only a small, constant number of hash operations per signing. Its core innovation enables verifiers to obtain one-time hash-based public keys without interacting with signers or third parties through secure computation. We formally prove the security of LiteQS in the random oracle model and evaluate its performance on commodity hardware and a resource-constrained 8-bit AtMega128A1 microcontroller. Experimental results show that LiteQS outperforms NIST PQ standards with lower computational overhead, minimal memory usage, and compact signatures. On an 8-bit microcontroller, it achieves up to 1.5–24×higher energy efficiency and 1.7–22×shorter signatures than PQ counterparts, and 56–76×better energy efficiency than conventional standards–enabling longer device lifespans and scalable, quantum-resilient authentication. 

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3. Towards Practical Post-quantum Signatures for Resource-Limited Internet of Things

   https://doi.org/10.1145/3485832.3488023  

   Behnia, Rouzbeh; Yavuz, Attila Altay (December 2021, In Annual Computer Security Applications Conference (ACSAC))

   A digital signature is an essential cryptographic tool to offer authentication with public verifiability, non-repudiation, and scalability. However, digital signatures often rely on expensive operations that can be highly costly for low-end devices, typically seen in the Internet of Things and Systems (IoTs). These efficiency concerns especially deepen when post-quantum secure digital signatures are considered. Hence, it is of vital importance to devise post-quantum secure digital signatures that are designed with the needs of such constraint IoT systems in mind. In this work, we propose a novel lightweight post-quantum digital signature that respects the processing, memory, and bandwidth limitations of resource-limited IoTs. Our new scheme, called ANT, efficiently transforms a one-time signature to a (polynomially bounded) many-time signature via a distributed public key computation method. This new approach enables a resource-limited signer to compute signatures without any costly lattice operations (e.g., rejection samplings, matrix multiplications, etc.), and only with a low-memory footprint and compact signature sizes. We also developed a variant for ANT with forward-security, which is an extremely costly property to attain via the state-of-the-art postquantum signatures. 

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4. Energy-Aware Digital Signatures for Embedded Medical Devices

   https://doi.org/10.1109/CNS.2019.8802675  

   Ozmen, Muslum Ozgur; Yavuz, Attila A.; Behnia, Rouzbeh (June 2019, IEEE Conference on Communications and Network Security (CNS))

   Authentication is vital for the Internet of Things (IoT) applications involving sensitive data (e.g., medical and financial systems). Digital signatures offer scalable authentication with non-repudiation and public verifiability, which are necessary for auditing and dispute resolution in such IoT applications. However, digital signatures have been shown to be highly costly for low-end IoT devices, especially when embedded devices (e.g., medical implants) must operate without a battery replacement for a long time. We propose an Energy-aware Signature for Embedded Medical devices (ESEM) that achieves near-optimal signer efficiency. ESEM signature generation does not require any costly operations (e.g., elliptic curve (EC) scalar multiplication/addition), but only a small constant-number of pseudo-random function calls, additions, and a single modular multiplication. ESEM has the smallest signature size among its EC-based counterparts with an identical private key size. We achieve this by eliminating the use of the ephemeral public key (i.e, commitment) in Schnorrtype signatures from the signing via a distributed construction at the verifier without interaction with the signer while permitting a constant-size public key. We proved that ESEM is secure (in random oracle model), and fully implemented it on an 8-bit AVR microcontroller that is commonly used in medical devices. Our experiments showed that ESEM achieves 8.4× higher energy efficiency over its closest counterpart while offering a smaller signature and code size. Hence, ESEM can be suitable for deployment on resource-limited embedded devices in IoT. We 

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5. Lightweight Digital Signatures for Internet of Things: Current and Post-Quantum Trends and Visions

   https://doi.org/10.1109/DSC61021.2023.10354177  

   Nouma, Saif E.; Yavuz, Attila A. (November 2023, IEEE)

   The Internet of Things (IoT) harbors a large number of resource-limited devices (e.g., sensors) that continuously generate and offload sensitive information (e.g., financial, health, personal). It is imperative the ensure the trustworthiness of this data with efficient cryptographic mechanisms. Digital signatures can offer scalable authentication with public verifiability and nonrepudiation. However, the state-of-the-art digital signatures do not offer the desired efficiency and are not scalable for the connected resource-limited IoT devices. This is without considering long term security features such as post-quantum security and forward security. In this paper, we summarize the main challenges to an energy-aware and efficient signature scheme. Then, we propose new scheme design improvements that uniquely embed different emerging technologies such as Mutli-Party Computation (MPC) and secure enclaves (e.g., Intel SGX) in order to secret-share confidential keys of low-end IoT devices across multiple cloud servers. We also envision building signature schemes with Fully Homomorphic Encryption (FHE) to enable verifiers to compute expensive commitments under encryption. We provide evaluation metrics that showcase the feasibility and efficiency of our designs for potential deployment on embedded devices in IoT. 

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