This thesis aims to facilitate the deployment of advanced cryptographic primitives in the real world. It does so by designing and implementing post-quantum algorithms on electronic travel documents, and multi-party computation (MPC) on smart meters. We also introduce a novel pairing-based key-and-message-homomorphic (KMHE) scheme for more efficient outsourced MPC. First, we present PQ-EAC, a post-quantum secure replacement for the Extended Access Control protocol used in electronic machine-readable travel documents (eMRTDs). By substituting Diffie-Hellman key exchange with post-quantum key encapsulation mechanisms, we design eight protocol variants offering different trade-offs between security and efficiency. Our implementation on an ARM SC300 chip demonstrates runtimes of under two seconds at typical data rates, confirming the practical feasibility of migrating eMRTDs to post-quantum security. Second, we develop the first fully privacy-preserving power flow analysis (PFA) based on MPC. By adopting a Cartesian formulation of Newton's method and exploiting sparsity, we create an efficient MPC implementation that enables smart grid operations without compromising prosumer privacy. Our benchmarks show that for small grids with low network latency, online computation completes in under 30 seconds, demonstrating that MPC-based PFA is practical for preventive smart grid applications.Third, we present a new KMHE scheme based on bilinear pairings that enables practical rerandomizable garbling schemes (RGS). Our construction reduces garbled gate size by 98.99% (from 133.43 MB to 1.35 MB) and garbling time by 99.998% (from 33 minutes to 0.04 seconds) compared to previous BHHO-based approaches. This four-order-of-magnitude improvement makes the SCALES protocol practically feasible for the first time, enabling constant-round outsourced computation with security against adaptive adversaries.Together, these contributions demonstrate that advanced cryptographic techniques can be made practical through careful protocol design, algorithmic optimization, and implementation strategies tailored to specific application constraints.
This thesis aims to facilitate the deployment of advanced cryptographic primitives in the real world. It does so by designing and implementing post-quantum algorithms on electronic travel documents, and multi-party computation (MPC) on smart meters. We also introduce a novel pairing-based key-and-message-homomorphic (KMHE) scheme for more efficient outsourced MPC. First, we present PQ-EAC, a post-quantum secure replacement for the Extended Access Control protocol used in electronic machine-readable travel documents (eMRTDs). By substituting Diffie-Hellman key exchange with post-quantum key encapsulation mechanisms, we design eight protocol variants offering different trade-offs between security and efficiency. Our implementation on an ARM SC300 chip demonstrates runtimes of under two seconds at typical data rates, confirming the practical feasibility of migrating eMRTDs to post-quantum security. Second, we develop the first fully privacy-preserving power flow analysis (PFA) based on MPC. By adopting a Cartesian formulation of Newton's method and exploiting sparsity, we create an efficient MPC implementation that enables smart grid operations without compromising prosumer privacy. Our benchmarks show that for small grids with low network latency, online computation completes in under 30 seconds, demonstrating that MPC-based PFA is practical for preventive smart grid applications.Third, we present a new KMHE scheme based on bilinear pairings that enables practical rerandomizable garbling schemes (RGS). Our construction reduces garbled gate size by 98.99% (from 133.43 MB to 1.35 MB) and garbling time by 99.998% (from 33 minutes to 0.04 seconds) compared to previous BHHO-based approaches. This four-order-of-magnitude improvement makes the SCALES protocol practically feasible for the first time, enabling constant-round outsourced computation with security against adaptive adversaries.Together, these contributions demonstrate that advanced cryptographic techniques can be made practical through careful protocol design, algorithmic optimization, and implementation strategies tailored to specific application constraints.
The advent of quantum computing presents a paradigm shift in modern cybersecurity, threatening the foundations of classical cryptographic systems such as RSA, ECC, and Diffie–Hellman key exchange. Quantum algorithms like Shor’s and Grover’s can efficiently break these schemes, rendering existing encryption mechanisms vulnerable and obsolete. This growing risk necessitates the development of quantum-resilient or post-quantum cryptographic (PQC) solutions that can safeguard data and computation in the era of quantum networks. Secure Multi-Party Computation (SMPC), a cornerstone of privacy-preserving computation, enables multiple entities to jointly compute a function over their private inputs without revealing them. However, its traditional security assumptions are also undermined by quantum threats. This research aims to explore and evaluate quantum-safe cryptographic protocols for integrating PQC into SMPC frameworks, thereby ensuring both confidentiality and correctness even in the presence of quantum-capable adversaries. The study focuses on lattice-based, hash-based, and code-based cryptographic primitives, analyzing their resilience, efficiency, and scalability when applied to distributed systems. A comparative framework is proposed to assess the performance and security trade-offs of different post-quantum SMPC implementations under realistic network conditions. The findings are expected to contribute to the design of a new class of cryptographic protocols capable of resisting quantum attacks, supporting the secure functioning of next-generation networks, and guiding policymakers and technologists toward practical post-quantum standardization. Ultimately, this research strengthens the bridge between theoretical cryptography and real-world cybersecurity readiness in the post-quantum era.
With the advancement of quantum computing, traditional public-key cryptographic algorithms are increasingly at risk of being broken. This paper investigates the applicability of post-quantum cryptography (PQC) within modernized power grid infrastructures, commonly known as smart grids, that rely heavily on interconnected and sometimes internet-facing devices and distributed control systems. To help safeguard these critical infrastructures against quantum-enabled threats, we benchmark and evaluate the performance of NIST-standardized and finalist PQC Key Encapsulation Mechanisms (KEMs) in a realistic smart grid testbed. Our evaluation includes both benchmarking of core cryptographic operations, key generation, encapsulation, and decapsulation, as well as full TLS 1.3 handshake benchmarking across a real network of embedded devices and smart grid nodes. A key contribution of this work is the development of a smart grid testbed spanning multiple buildings with distributed energy resources (DERs) such as batteries and photovoltaic arrays, enabling an in-depth, system-level evaluation of post-quantum key exchange protocols in this context. We conclude by discussing the trade-offs between algorithmic efficiency and system constraints such as bandwidth, key rotation frequency, and device capability. Our findings offer actionable recommendations for the deployment of PQC algorithms tailored to the smart grid.
The advent of quantum computing poses a significant threat to the security of current cryptographic systems, including those underpinning secure multi-party computation (MPC). While considerable research has focused on developing post-quantum cryptographic (PQC) primitives, their integration into MPC protocols often inherits the computational security assumptions characteristic of classical cryptography. This paper explores the information-theoretic foundations for designing and analyzing post-quantum secure MPC protocols, aiming to achieve security guarantees that are independent of computational hardness assumptions and resilient against adversaries with unbounded computational power, including quantum adversaries. We delve into how information-theoretic primitives, such as secret sharing and oblivious transfer, can be adapted or combined with post-quantum techniques to construct MPC protocols with enhanced security. The work reviews existing paradigms, identifies challenges in achieving robust post-quantum information-theoretic security, and proposes conceptual frameworks for constructing such protocols. We examine the trade-offs between information-theoretic security, efficiency, and the practical implementation of post-quantum MPC, offering a theoretical perspective on how to achieve strong, long-term security in a quantum era. Our findings suggest that a hybrid approach, leveraging the strengths of both information theory and carefully selected post-quantum primitives, is crucial for building resilient MPC solutions.
The advent of quantum computing poses an existential threat to contemporary cryptographic standards, particularly those securing decentralized blockchain networks and cloud infrastructures.Classical public-key cryptosystems such as RSA, ECC, and DH, which rely on factorization and discrete logarithm problems, are rendered obsolete by Shor's algorithm, necessitating the transition toward post-quantum cryptographic (PQC) solutions.This study explores the integration of PQC algorithms, including lattice-based, hash-based, code-based, multivariate, and isogeny-based cryptographic mechanisms, within blockchain-ledger technologies and cloud architectures to ensure long-term security against quantum adversaries.A comparative analysis is conducted to evaluate computational efficiency, key size implications, communication overhead, and security resilience under quantum attack models.The research highlights the adaptation of PQC within blockchain consensus mechanisms, smart contract execution, and cryptographic primitives such as digital signatures, zero-knowledge proofs, and secure multi-party computation (MPC).Additionally, it examines the impact of PQC on cloud security, addressing challenges in quantum-safe key exchange protocols, homomorphic encryption for secure computations, and cross-platform interoperability within hybrid quantum-classical cloud ecosystems.Real-world implementations and benchmarking data provide insights into the feasibility of large-scale adoption, shedding light on standardization efforts by NIST and industry consortia.The study concludes with future directions, emphasizing the need for efficient PQC algorithm optimization, lightweight cryptographic frameworks for IoT-driven blockchain applications, and scalable post-quantum identity management systems.By establishing quantum-resistant security frameworks, this research underscores the imperative need for early adoption to mitigate cryptographic vulnerabilities in the impending post-quantum era.
Abstract The rapid evolution of quantum computing fundamentally threatens modern cryptographic infrastructures, necessitating a paradigm shift toward advanced encryption techniques. While post-quantum cryptography (PQC) ensures that data remains secure against quantum algorithmic decryption, it does not inherently facilitate the processing of that data in untrusted environments. Homomorphic encryption (HE) addresses this computational privacy requirement, yet traditional HE schemes rely on classical mathematical problems that are easily compromised by quantum systems. This paper presents a comprehensive comparative framework that integrates post-quantum cryptographic principles with homomorphic capabilities to enable quantum-resistant, privacy-preserving computation. By analyzing lattice-based algorithms, code-based cryptography, and hardware acceleration paradigms, this study maps the existing trade-offs between security, computational overhead, and practical deployment feasibility in the impending quantum era. Keywords: PQC, HE. 1.Introduction The rapid evolution of quantum computing technology presents a profound threat to modern cryptographic infrastructures. As quantum algorithms, notably Shor's algorithm, mature, they acquire the capability to solve nondeterministic polynomial time problems in polynomial time, thereby breaking traditional asymmetric encryption standards such as RSA and Elliptic Curve Cryptography (ECC) (Chen, 2024). Consequently, the development of post-quantum cryptography (PQC) has become a global imperative to secure sensitive communications and data against future quantum adversaries (Pranjal & Chaturvedi, 2024). Cryptographers are currently focusing on transitioning secure systems to these newly established PQC standards before large-scale quantum computers become commercially viable. While PQC addresses the secure transmission and storage of data, it does not inherently solve the problem of secure data processing in untrusted cloud environments. Homomorphic encryption (HE) provides a sophisticated mechanism that allows computations to be performed directly on encrypted data without requiring prior decryption (Jain & Cherukuri, 2023). The core problem addressed in this paper is the conceptual and practical integration of PQC with HE shown in Fig1.1 which is essential for ensuring quantum-safe, privacy-preserving computation in distributed architectures. Achieving this synthesis is highly complex due to the massive computational overhead and noise accumulation inherent to both cryptographic domains. However, existing approaches to privacy-preserving computation remain broadly insufficient for the post-quantum era. First, conventional homomorphic encryption schemes rely heavily on mathematical hardness assumptions, such as integer factorization or discrete logarithms, which are demonstrably vulnerable to quantum attacks (Chen, 2024). Second, while some high-performance fully homomorphic implementations exist, they suffer from prohibitive computational overhead and severe ciphertext expansion, making widespread deployment impractical without specialized mitigation strategies (Tseng et al., 2025). Third, hardware-accelerated privacy solutions often rely on trusted execution environments, like Intel SGX, which inherently introduce side-channel vulnerabilities and force reliance on centralized hardware trust rather than pure mathematical security (Sadat et al., 2017). To overcome these critical limitations, this paper proposes a structured comparative methodology for evaluating quantum-resistant homomorphic encryption systems. Specifically, our paper makes the following main contributions: We provide a comprehensive comparative framework that categorizes and evaluates lattice-based and code-based homomorphic encryption schemes against classical performance constraints. We propose a structured, hypothetical evaluation pipeline designed to benchmark the computational overhead and latency of post-quantum homomorphic algorithms in federated networking environments. 2.Privacy-preserving computation The literature surrounding privacy-preserving computation can be broadly classified into three primary categories, the first being classical and fully homomorphic encryption (FHE) systems. The core idea behind these schemes is the preservation of algebraic structures during encryption, allowing operations on ciphertexts to reflect directly on the underlying plaintexts without exposing the raw data (Jain & Cherukuri, 2023). A major strength of these classical FHE systems, such as those utilized in encrypted relational databases like FHE-SQL, is their ability to provide end-to-end cryptographic protection for queries without relying on trusted hardware modules (Tseng et al., 2025). However, a fundamental weakness is that early FHE models, and their underlying privacy homomorphisms, remain fundamentally susceptible to quantum cryptanalysis due to their reliance on classical mathematical problems (Sen, 2013). Compared to these classical paradigms, our work specifically focuses on migrating these operational homomorphic properties into genuinely quantum-safe mathematical frameworks. The second category of related work focuses on hardware acceleration and hybrid computational environments for homomorphic encryption. The core idea here involves leveraging specialized hardware, such as ASIC AI chips or coarse-grained compute architectures like Google's TPUs, to mitigate the enormous computational overhead associated with HE (Tong et al., 2025). The strength of this approach lies in its ability to bridge the energy-efficiency gap, often utilizing intelligent compiler frameworks to convert high-precision modular arithmetic into dense, low-precision matrix multiplications. Conversely, the weakness of hardware-centric methods is that architectural mismatches frequently lead to severe resource under-utilization, and hybrid solutions utilizing components like Intel SGX introduce hardware trust assumptions that can compromise pure cryptographic integrity (Sadat et al., 2017). Unlike these approaches, our framework prioritizes algorithmic resilience and quantum resistance over purely hardware-driven and enclave-based optimizations. The third category encompasses emerging post-quantum and quantum homomorphic paradigms, which seek to unify quantum resistance with computational privacy. Researchers have proposed lattice-based HE schemes to replace vulnerable legacy systems like Paillier and ElGamal, successfully enabling secure applications such as federated learning (Chen, 2024). Similarly, code-based cryptography utilizing McEliece and non-negative matrix factorization has shown promise in providing faster encryption and decryption times while remaining mathematically secure against quantum computers (Chen, 2024). Furthermore, advanced quantum homomorphic encryption protocols have explored information-theoretic security combined with homomorphic quantum error-correction to ensure future-proof data protection (Ouyang & Rohde, 2022). While these systems represent the state-of-the-art, their primary weakness remains the massive memory and communication overhead introduced during distributed training protocols, which negatively impacts classification performance. Our approach builds upon this category by proposing a standardized methodology to systematically compare these disparate post-quantum homomorphic techniques. 3.Multi-stage Method To systematically evaluate and deploy post-quantum homomorphic encryption, we propose a structured, multi-stage methodological framework. The first step involves cryptographic primitive selection, where system architects must evaluate and choose between lattice-based constructs, such as ML-KEM adaptations, and code-based systems like McEliece, depending on their domain constraints (Chen, 2024). The second step requires the implementation of an algorithmic parameter optimization module, which dynamically adjusts polynomial degrees and error distributions to balance security levels with the operational multiplicative depth required by the application. Finally, the third step comprises the integration of a specialized abstraction layer designed to map complex high-precision cryptographic operations into hardware-friendly matrix operations, thereby reducing the inherent bottleneck of ciphertext evaluation. The key design choices within this framework are driven by the absolute necessity to balance quantum resistance with practical algorithmic utility. We prioritize lattice-based cryptography for our primary evaluation pathway because of its established resilience against quantum threats and its recent standardization by the National Institute of Standards and Technology (NIST) (Chen, 2024). Additionally, we explicitly design our framework to avoid reliance on trusted hardware environments, opting instead for pure cryptographic guarantees to prevent the side-channel data leaks that often plague hardware-enclave solutions. By focusing on algorithmic alignment and basis-aligned mathematical transformations, the framework ensures that homomorphic workloads can be optimized effectively without compromising the underlying post-quantum security proofs. To validate the efficacy of the proposed framework, we outline a comprehensive evaluation plan utilizing a hypothetical, high-dimensional healthcare benchmarking dataset. The experimental setup will simulate a secure genome-wide association study (GWAS) executing within a fully decentralized federated learning environment (Sadat et al., 2017). The primary metrics for this hypothetical evaluation will include key generation latency, ciphertext expansion ratio, and the amortized computational time required for homomorphic multiplication operations across distributed nodes. By systematically varying the cryptographic noise parameters and observing the resulting degradation in analytical performance, we aim to empirically map the trad
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.