arXiv subjects

Abel C. H. Chen

Publications and source records attributed to Abel C. H. Chen.

At least 19 recordsLinked to original sources

arXiv2026

Quantum-Safe Web Service Architecture Using Time-Based One-Time Passwords

One-Time Passwords (OTPs) have become a common option for multi-factor authentication in several applications. For instance, during website login processes, OTPs are often used in conjunction with traditional text-based usernames and passwords to verify whether the access request originates from a legitimate human user rather than an automated agent. However, in scenarios involving automated connections and system-to-system interoperability, Time-Based One-Time Passwords (TOTPs) may be required to establish secure connections and access Web Services (WSs). Therefore, this study focuses on exploring the development of a quantum-safe web service architecture. The proposed approach achieves transmission security management by implementing Transport Layer Security (TLS) and HyperText Transfer Protocol Secure (HTTPS) based on Post-Quantum Cryptography (PQC). Furthermore, web service security management is realized through the construction of keyed-Hash Message Authentication Code (HMAC)-driven TOTPs. Within the experimental environment, this study evaluates and compares the computational performance of the Secure Hash Algorithm-2 (SHA-2), SHA-3, Ascon-Hash256, and SM3. The required computation time under different hardware resource conditions is analyzed for future web service deployment.

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arXiv2026

Multivariate Cryptography-Based Anonymous Certificate Scheme

As quantum computing technology continues to mature, the US National Institute of Standards and Technology (NIST) has outlined a migration timeline for Post-Quantum Cryptography (PQC), recommending the deprecation of certain elliptic curve cryptography (ECC) by 2030. Furthermore, privacy-sensitive application scenarios, such as vehicular communications, require the use of anonymous certificates. However, existing anonymous certificate schemes are still largely based on ECC. Therefore, this study proposes a multivariate cryptography-based anonymous certificate scheme, aiming to design quantum-safe anonymous certificates suitable for privacy-sensitive application services. The proposed multivariate cryptography-based anonymous certificate scheme is supported by rigorous mathematical proofs and illustrated with computational cases.

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arXiv2026

Pseudonym Scheme Based on Hybrid Certificates for Security Credential Management System in Vehicular Communications

In recent years, the Institute of Electrical and Electronics Engineers (IEEE) and the European Telecommunications Standards Institute (ETSI) have developed a series of security communication standards for vehicular communications. These standards include mechanisms such as the Security Credential Management System (SCMS) and Butterfly Key Expansion (BKE) to protect vehicle privacy. However, these standards are mainly based on the Elliptic-Curve Cryptography (ECC), which may be vulnerable to attacks from quantum computing in the future. In response to this potential risk, this study proposes a hybrid certificate that combines the ECC with Post-Quantum Cryptography (PQC). This approach enables infrastructure systems to be built on cryptographic foundations that are more resilient to quantum-based attacks. Furthermore, this study presents a generalized pseudonym scheme that is compatible with various cryptographic algorithms for generating pseudonym certificates. This design aims to eliminate the possibility of inferring any correlation between the public key in a pseudonym certificate and that in an enrollment certificate. This study also conducts a comprehensive performance evaluation of the RSA, ECC, and PQC algorithms, particularly those standardized by the National Institute of Standards and Technology (NIST). The comparison considers factors such as message length and computation time. Based on the findings, this study recommends suitable pseudonym schemes that adopt hybrid certificates for secure and efficient use in vehicular communications.

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arXiv2026

Key Encapsulation Mechanism-Based Integrated Encryption Scheme (KEM-IES)

The Elliptic Curve Integrated Encryption Scheme (ECIES) is widely regarded as a practical method and has been adopted by multiple standards. However, the advancement of quantum computing technologies poses potential security risks to ECIES. Therefore, this study proposes a Key Encapsulation Mechanism-Based Integrated Encryption Scheme (KEM-IES), which enhances resistance to quantum attacks by incorporating a Post-Quantum Cryptography (PQC)-based Key Encapsulation Mechanism (KEM). Furthermore, the study integrates the Ascon algorithm, released by the National Institute of Standards and Technology (NIST) in August 2025, to further improve computational efficiency and enable applicability to embedded systems. The proposed KEM-IES and its Ascon-based variant are implemented on a Raspberry Pi 4, and evaluations are conducted to compare the performance of ECIES and KEM-IES.

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arXiv2026

Post-Quantum Cryptography-Based Bidirectional Authentication Key Exchange Protocol and Industry Applications: A Case Study of Instant Messaging

This study aims to enhance the bidirectional authentication capability of ML-KEM (Module-Lattice-Based Key-Encapsulation Mechanism) by proposing the post-quantum cryptography-based (PQC-based) bidirectional authentication key exchange protocol. Furthermore, it introduces dual-usage certificates combining PQC-based DSA (Digital Signature Algorithm) and PQC-based KEM, which include composite schemes, catalyst schemes, and chameleon schemes. These dual-usage certificates utilize the PQC-based DSA public key and PQC-based KEM public key within the certificate to meet the requirements for bidirectional authentication and encryption, enabling the negotiation of a shared secret key. During the experimental phase, the study validates and compares key exchange message lengths and computation times under different certificate configurations. Finally, instant messaging is presented as an industry application to demonstrate the practical implementation of the proposed protocol.

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arXiv2026

Comparison of Credential Management Systems Based on the Standards of IEEE, ETSI, and YD/T 3957-2021

As V2X (Vehicle-to-Everything) technology becomes increasingly prevalent, the security of V2X networks has garnered growing attention worldwide. In North America, the IEEE 1609 series standards are primarily used, while Europe adopts the ETSI series standards, and China has also established its industry standard, YD/T 3957-2021, among others. Although these standards share some commonalities, they also exhibit differences. To achieve compatibility across these standards, analyzing their similarities and differences is a crucial issue. Therefore, this study focuses on analyzing the three major standards mentioned above, discussing aspects such as certificate formats, signed message formats, and certificate request processes. Additionally, this research evaluates the efficiency of different cryptographic methods, including NIST P-256 and SM2-256, SHA-256 and SM3-256, as well as AES-128 and SM4-128. Finally, the study implements these three major standards on V2X devices and compares the efficiency of message signing and signature verification in V2X systems, providing a reference for the development of a secure certificate management system for V2X networks.

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arXiv2026

Implementation Challenges in Quantum Key Distribution

In recent years, quantum computing technologies have steadily matured and have begun to find practical applications across various domains. One important area is network communication security, where Quantum Key Distribution (QKD) enables communicating parties to establish a shared secret that can then be used to generate symmetric keys for subsequent encryption and decryption. This study focuses on implementing and comparing two well-known QKD protocols, namely BB84 and E91, within an actual quantum computing environment. It also proposes the use of SX gate operations to generate uniform quantum superposition states. By leveraging the properties of quantum superposition and quantum entanglement, the study illustrates how communicating parties can securely obtain a shared secret while preventing adversaries from intercepting it. The experiments are conducted using the IBM Quantum Platform to demonstrate the feasibility of the BB84 and E91 protocols on actual quantum hardware. The evaluation considers several metrics, including entropy, Independent and Identically Distributed (IID), and error-rate verifications.

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arXiv2026

Post-Quantum Cryptography Key Expansion Method and Anonymous Certificate Scheme Based on NTRU

NTRU is one of the important lattice-based post-quantum cryptography methods, offering resistance against quantum computing attacks. However, a drawback of NTRU lies in its relatively low efficiency in generating key pairs. Therefore, this study proposes an NTRU-based key expansion method that enables efficient public key expansion. Furthermore, the proposed method is applied to an anonymous certificate scheme, allowing an end entity to generate a key pair only once, after which the certificate authority can expand multiple distinct public keys for anonymity. The experimental results demonstrate that the proposed key expansion method achieves significantly higher efficiency than key pair generation.

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arXiv2025

Deterministic Random Bit Generators Based on Ascon for Embedded Systems

As the Deterministic Random Bit Generator (DRBG) serves as a fundamental component in random number generation and cryptographic applications, its performance and security are particularly critical in resource-constrained embedded systems, where memory capacity and computational efficiency are limited. Establishing a high-performance and secure DRBG is therefore an important issue for embedded system design. Furthermore, the National Institute of Standards and Technology (NIST) established the Ascon lightweight cryptographic standard in August 2025, which is suitable for use in resource-limited embedded environments. Therefore, this study revises the DRBG standard and proposes three Ascon-driven constructions: the Ascon-Driven Hash-Based DRBG, the Ascon-Driven keyed-Hash Message Authentication Code (HMAC) DRBG, and the Ascon-Driven Counter-mode (CTR) DRBG. In the experiments, these methods are implemented on a Raspberry Pi platform. The experimental results demonstrate that the proposed approaches achieve higher computational efficiency and lower memory usage compared with existing DRBG implementations, making them suitable for deployment in embedded systems.

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arXiv2025

A Comparative Study of Hybrid Post-Quantum Cryptographic X.509 Certificate Schemes

As quantum computing hardware continues to advance, the integration of such technology with quantum algorithms is anticipated to enable the decryption of ciphertexts produced by RSA and Elliptic Curve Cryptography (ECC) within polynomial time. In response to this emerging threat, the U.S. National Institute of Standards and Technology (NIST) finalized a series of Post-Quantum Cryptography (PQC) standards in August 2024 and outlined a roadmap for PQC migration. Consequently, the design of X.509 certificates that adhere to PQC standards has become a crucial focus in the development of certificate management systems. To further strengthen security and facilitate a smooth migration process, several hybrid certificate schemes have been proposed internationally based on the X.509 certificate format, including the composite scheme, the catalyst scheme, and the chameleon scheme. This study presents a comprehensive analysis and comparison of these hybrid certificate schemes from multiple perspectives (e.g., certificate size, computational efficiency, and migration feasibility) to assess their suitability for various applications and services.

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arXiv2025

Hybrid Schemes of NIST Post-Quantum Cryptography Standard Algorithms and Quantum Key Distribution for Key Exchange and Digital Signature

Since the security of post-quantum cryptography (PQC) algorithms is based on the hardness of mathematical problems, while the security of quantum key distribution (QKD) relies on the fundamental principles of quantum physics, each approach possesses distinct advantages and limitations that can complement one another. Consequently, recent studies have proposed hybrid schemes that combine QKD and PQC to establish a dual-layered security model. In response to this trend, this study proposes hybrid schemes that integrate QKD with the National Institute of Standards and Technology (NIST) standardized PQC algorithms. These hybrid schemes include two core components: a hybrid QKD-PQC key exchange protocol and a hybrid QKD-PQC digital signature scheme. For the hybrid key exchange protocol, this study combines Module-Lattice-based Key Encapsulation Mechanisms (ML-KEM) with QKD protocols, specifically BB84 and E91, to construct a secure key exchange protocol. In the design of the hybrid digital signature scheme, this study utilizes Module-Lattice-based Digital Signature Algorithms (ML-DSA) and Stateless Hash-based Digital Signature Algorithms (SLH-DSA) to generate signature reconstruction values. These values are verified using confirmation codes transmitted via the BB84 and E91 protocols. The proposed hybrid key exchange protocol is evaluated by examining the shared secret key it produces, particularly with respect to entropy and whether the output is independent and identically distributed (IID). Furthermore, the computation time and message lengths of the proposed hybrid schemes are evaluated.

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arXiv2025

Secure Password Generator Based on Secure Pseudo-Random Number Generator

In recent years, numerous incidents involving the leakage of website accounts and text passwords (referred to as passwords) have raised significant concerns regarding the potential exposure of personal information. These events underscore the critical importance of both information security and password protection. While many of these breaches are attributable to vulnerabilities within website infrastructure, the strength and security of the passwords themselves also play a crucial role. Consequently, the creation of secure passwords constitutes a fundamental aspect of enhancing overall system security and protecting personal data. In response to these challenges, this study presents a secure password generation approach utilizing a cryptographically secure Pseudo-Random Number Generator (PRNG). The generator is implemented using a range of Message Authentication Code (MAC) algorithms, including the Keyed-Hash Message Authentication Code (HMAC), Cipher-based Message Authentication Code (CMAC), and KECCAK Message Authentication Code (KMAC), to produce robust random values suitable for password generation. To evaluate the proposed method, empirical assessments were conducted in accordance with the guidelines provided in the National Institute of Standards and Technology (NIST) Special Publication (SP) 800-90B. The evaluation focused on two primary aspects: entropy estimation and verification of independent and identically distributed (IID) properties. Experimental results indicate that the proposed method satisfies both entropy and IID requirements, thereby demonstrating its ability to generate passwords with a high degree of randomness and security.

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arXiv2025

NIST Post-Quantum Cryptography Standard Algorithms Based on Quantum Random Number Generators

In recent years, the advancement of quantum computing technology has posed potential security threats to RSA cryptography and elliptic curve cryptography. In response, the National Institute of Standards and Technology (NIST) published several Federal Information Processing Standards (FIPS) of post-quantum cryptography (PQC) in August 2024, including the Module-Lattice-Based Key-Encapsulation Mechanism (ML-KEM), Module-Lattice-Based Digital Signature Algorithm (ML-DSA), and Stateless Hash-Based Digital Signature Algorithm (SLH-DSA). Although these PQC algorithms are designed to resist quantum computing attacks, they may not provide adequate security in certain specialized application scenarios. To address this issue, this study proposes quantum random number generator (QRNG)-based PQC algorithms. These algorithms leverage quantum computing to generate random numbers, which serve as the foundation for key pair generation, key encapsulation, and digital signature generation. A generalized architecture of QRNG is proposed, along with the design of six QRNGs. Each generator is evaluated according to the statistical validation procedures outlined in NIST SP 800-90B, including tests for verification of entropy sources and independent and identically distributed (IID) outputs. Experimental results assess the computation time of the six QRNGs, as well as the performance of QRNG-based ML-KEM, QRNG-based ML-DSA, and QRNG-based SLH-DSA. These findings provide valuable reference data for future deployment of PQC systems.

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arXiv2025

A Comparative Study and Implementation of Key Derivation Functions Standardized by NIST and IEEE

Since many applications and services require pseudorandom numbers (PRNs), it is feasible to generate specific PRNs under given key values and input messages using Key Derivation Functions (KDFs). These KDFs are primarily constructed based on Message Authentication Codes (MACs), where the MAC serves as a core component in the generation of pseudorandom numbers. In light of this, the study first examines three MAC algorithms defined by the National Institute of Standards and Technology (NIST): the Keyed-Hash Message Authentication Code (HMAC), the Cipher-based Message Authentication Code (CMAC), and the Keccak-based Message Authentication Code (KMAC). Subsequently, the study explores KDFs based on these MACs, including the Counter Mode KDF, the KMAC-based KDF, and the KDF defined in IEEE 1609.2.1. In experiments, the computation times for generating MACs and the corresponding pseudorandom numbers using each KDF are evaluated. The study further analyzes the advantages, disadvantages, and applicable scenarios for each method. Experimental results indicate that the CMAC and the CMAC-based KDF exhibit the shortest computation times, averaging approximately 0.007 milliseconds and 0.014 milliseconds, respectively.

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arXiv2025

HQSI: Hybrid Quantum Swarm Intelligence -- A Case Study of Online Certificate Status Protocol Request Flow Prediction

As quantum computing technology continues to advance, various sectors, including industry, government, academia, and research, have increasingly focused on its future applications. With the integration of artificial intelligence techniques, multiple Quantum Neural Network (QNN) models have been proposed, including quantum convolutional neural networks, quantum long short-term memory networks, and quantum generative adversarial networks. Furthermore, optimization methods such as constrained optimization by linear approximation and simultaneous perturbation stochastic approximation have been explored. Therefore, this study proposes Hybrid Quantum Swarm Intelligence (HQSI), which constructs a QNN model as a forward propagation neural network. After measuring quantum states and obtaining prediction results, a classical computer-based swarm intelligence algorithm is employed for weight optimization. The training process iterates between quantum and classical computing environments. During the experimental phase, the proposed HQSI method is evaluated using an online certificate status protocol request traffic prediction task. Comparative analysis against state-of-the-art quantum optimization algorithms demonstrates that the proposed HQSI approach achieves more than a 50% reduction in error.

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arXiv2025

Implementation of Shor Algorithm: Factoring a 4096-Bit Integer Under Specific Constraints

In recent years, advancements in quantum chip technology, such as Willow, have contributed to reducing quantum computation error rates, potentially accelerating the practical adoption of quantum computing. As a result, the design of quantum algorithms suitable for real-world applications has become a crucial research direction. This study focuses on the implementation of Shor algorithm, aiming to improve modular computation efficiency and demonstrate the factorization of a 4096-bit integer under specific constraints. Experimental results, when compared with state-of-the-art (SOTA) methods, indicate a significant improvement in efficiency while enabling the factorization of longer integers.

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arXiv2025

Man-in-the-Middle Attacks Targeting Quantum Cryptography

The development of the Willow quantum chip by Google has sparked significant interest in quantum computing, ushering in a new wave of advancements in the field. As quantum computing technology continues to mature, secure quantum communication has garnered increasing attention. To establish secure communication, several quantum key distribution (QKD) protocols have been proposed, such as the BB84 protocol, which leverages the principles of quantum superposition and other quantum properties to ensure secure transmission. However, existing QKD protocols may face vulnerabilities under certain conditions. This study proposes two types of man-in-the-middle (MITM) attack techniques and demonstrates their potential to compromise quantum cryptography through practical case studies. Furthermore, this study proposes strategies to counteract these MITM attacks and proposes methods to enhance the security of quantum cryptographic systems. The findings offer valuable insights for the future implementation and deployment of secure quantum communication systems.

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arXiv2025

Hybrid Scheme of Post-Quantum Cryptography and Elliptic-Curve Cryptography for Certificates -- A Case Study of Security Credential Management System in Vehicle-to-Everything Communications

Due to the current standard of Security Credential Management System (SCMS) for Vehicle-to-Everything (V2X) communications using asymmetric cryptography, specifically Elliptic-Curve Cryptography (ECC), which may be vulnerable to quantum computing attacks. Therefore, the V2X SCMS is threatened by quantum computing attacks. However, although the National Institute of Standards and Technology (NIST) has already selected Post-Quantum Cryptography (PQC) algorithms as the standard, the current PQC algorithms may have issues such as longer public key lengths, longer signature lengths, or lower signature generation and verification efficiency, which may not fully meet the requirements of V2X communication applications. In view of the challenges in V2X communication, such as packet length, signature generation and verification efficiency, security level, and vehicle privacy, this study proposes a hybrid certificate scheme of PQC and ECC. By leveraging the strengths of both PQC and ECC, this scheme aims to overcome the challenges in V2X communication. PQC is used to establish a security level resistant to quantum computing attacks, while ECC is utilized to establish anonymous certificates and reduce packet length to meet the requirements of V2X communication. In the practical experiments, the study implemented the SCMS end entity based on the Chunghwa Telecom SCMS and the Clientron On-Board Unit (OBU) to conduct field tests in Danhai New Town in New Taipei City. The performance of various existing hybrid certificate schemes combining PQC (e.g., Dilithium, Falcon, and SPHINCS+) and ECC is compared, and a practical solution is provided for V2X industries.

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