Classical public-key cryptography, mainly RSA, is at risk from the emergence of quantum computers. A complete shift to Post-Quantum Cryptography (PQC) faces vulnerabilities due to implementation and trust issues, despite NIST's approval of standards such as ML-KEM (Kyber). This paper presented a performance and bandwidth trade-off study of a proposed Hybrid Key Encapsulation Mechanism that fused the NIST-standardized ML-KEM-768 (FIPS 203) with the traditional RSA-3072. Two separate secret keys S1 and S2 were produced and encapsulated utilizing both classical and post-quantum public keys in our dual-layered model. In order to create a strong session key that ensures trust transition and backward compatibility with current network infrastructures, these secrets were then combined using a Hybrid Key Derivation Function (HKDF). In comparison to standalone systems, the study assessed the computational cost and communication latency brought about by this hybrid overhead. According to experimental data, the hybrid architecture offers a crucial security fail-safe against both classical flaws and future quantum threats without prohibitively high performance, even though it increases ciphertext size.
Classical public-key cryptography, mainly RSA, is at risk from the emergence of quantum computers. A complete shift to Post-Quantum Cryptography (PQC) faces vulnerabilities due to implementation and trust issues, despite NIST's approval of standards such as ML-KEM (Kyber). This paper presented a performance and bandwidth trade-off study of a proposed Hybrid Key Encapsulation Mechanism that fused the NIST-standardized ML-KEM-768 (FIPS 203) with the traditional RSA-3072. Two separate secret keys S1 and S2 were produced and encapsulated utilizing both classical and post-quantum public keys in our dual-layered model. In order to create a strong session key that ensures trust transition and backward compatibility with current network infrastructures, these secrets were then combined using a Hybrid Key Derivation Function (HKDF). In comparison to standalone systems, the study assessed the computational cost and communication latency brought about by this hybrid overhead. According to experimental data, the hybrid architecture offers a crucial security fail-safe against both classical flaws and future quantum threats without prohibitively high performance, even though it increases ciphertext size.
The emergence of fault-tolerant quantum computing poses an existential threat to classical public-key cryptographic systems, including RSA and Elliptic Curve Cryptography (ECC), through Shor's polynomial-time factorization algorithm. The Harvest Now, Decrypt Later (HNDL) attack paradigm further amplifies this threat by enabling adversaries to archive ciphertext today for future quantum-enabled decryption, rendering long-term data confidentiality immediately at risk. While the National Institute of Standards and Technology (NIST) finalized post-quantum cryptographic standards ML-KEM (FIPS 203) and ML-DSA (FIPS 204) in August 2024, their practical integration into complete application-level communication systems remains a largely unaddressed research gap. This paper presents QuantumShield, a hybrid post-quantum secure peer-to-peer communication platform that integrates ML-KEM-768 for quantum-safe key encapsulation, ML-DSA-65 for authenticated digital signatures, and AES-256-GCM for high-throughput symmetric encryption. Our primary research contribution is a rigorous empirical analysis of PQC integration overhead in a real-world communication pipeline, quantifying latency, key size, and security trade-offs against classical RSA-2048 and ECC-256 baselines under controlled experimental conditions. Experimental evaluation across 1,000 iterations demonstrates that ML-KEM-768 encapsulation completes in 2.8 ± 0.2 ms compared to 4.1 ± 0.3 ms for ECDH key agreement — a 32% latency reduction while providing NIST Level 3 post-quantum security. The complete secure transfer pipeline processes 1 MB files in under 22 ms on commodity hardware. The system further provides interactive cryptographic visualization, adversary threat modeling, tamper detection simulation, and a hybrid migration framework demonstrating practical transition from classical to post-quantum infrastructure. QuantumShield establishes that quantum-safe communication is not merely theoretical but deployable today with negligible performance compromise.
This paper describes a hybrid key-encapsulation mechanism (KEM): a way for two parties to agree on a shared 32-byte secret that stays safe as long as either of two very different building blocks remains unbroken. The first building block is classical RSA-2048. The second is ML-KEM-768, the lattice-based KEM that NIST standardized as FIPS 203. We run both, then mix their two secrets with HKDF-SHA-256 to produce one session key. The pay-off is simple: an attacker has to break both RSA and ML-KEM to learn the session key, so the scheme protects you today (when RSA is strong) and continues to protect you after a quantum computer breaks RSA (when ML-KEM carries the load). A second, independent idea appears here only as an engineering optimization: the Furui 6n±1 sieve, a fast way to generate RSA primes. We are explicit that the sieve contributes nothing to security — it just makes classical key generation cheaper during the migration period, when systems keep minting new RSA keys. We prove this carefully so that no reader mistakes a performance trick for a security feature. The paper is written for engineers who want to deploy a hybrid KEM correctly. The main text explains the construction, the threat model, and how to implement it safely. The appendices give the full formal security reduction, the statistical validation of the sieve, and a reproducible benchmark methodology for readers who want the underlying detail.
The fast development of cyber communications, multimedia distribution, remote working have promoted the demand to transmit sensitive information through secure means in both the public and the private networks. The advent of massive quantum computers is rendering traditional cryptographic algorithms like RSA and Elliptic Curve Cryptography (ECC) insecure because they can crack the classical public-key algorithms like the Shor and Grover algorithms. This brings an immediate need of hybrid cryptographic systems, which integrate classical, quantum, and post-quantum algorithms to provide confidentiality, integrity, authentication, and future security beyond the quantum threat horizon.The paper is a proposal of a Hybrid Quantum-Post-Quantum Cryptographic Framework of transmitting files safely. It starts by aggregating files, which is a process to compress several files, images, videos, and multimedia files that users have chosen into one file to minimize redundancy and ease encryption. The AES-256 encrypted file is in GCM mode and provides confidentiality and integrity of the compressed file.The dual-layer mechanism ensures key establishment security. To begin with, Quantum Key Distribution (QKD) based on the protocols of BB84/E91 allows the Sender and the Receiver to generate a Quantum Secret Key (QSK) by exchanging quantum bits in quantum channel. Constant monitoring of the error rate facilitates automatic eavesdropping detection, and guarantees the keys generation is made when the conditions are secure, as well as the safeguarding of interception and man-in-the-middle attacks.A post-quantum layer is provided to ensure long-term security against quantum cryptanalysis, which uses Kyber, a NIST-approved lattice-based Key Encapsulation Mechanism (KEM). The Receiver creates a key pair of Kyber and disseminates the public key to the Sender. By using encapsulation, the Sender gets a PQC ciphertext and a Shared Secret (SS), with decapsulation on the Receiver side giving ensure that only participants of good faith get the same secret value.The hybridization phase consists of combining the QSK of QKD and SS of Kyber with the help of HKDF-SHA256 to obtain a Final Wrap Key (FWK). AES-GCM encrypts the key of file encryption by wrapping it with FWK which allows a secure and authenticated transfer of the key. The Sender sends four messages: encrypted file, Kyber ciphertext, wrapped AES key and the initialisation vector. At Receiver end, FWK is calculated once again with the help of QSK and SS so that the original data can be decrypted with the help of AES key.The suggested framework provides a defense-in-depth solution based on the combination of quantum security, post-quantum resilience and authenticated symmetric encryption. It can be analyzed that there is a strong resistance to classical and quantum adversaries, scalability, and compatibility with the existing communication networks. This renders the model to be appropriate to secure government communication, military systems, data exchange in healthcare environments, cloud storage and financial infrastructures. Keywords— Quantum Key Distribution (QKD), Post-Quantum Cryptography (PQC), Kyber,Key Encapsulation Mechanism (KEM), HKDF-SHA256, Quantum Secret Key (QSK), GCM Mode.
The advent of cryptographically relevant quantum computers poses an existential threat to current public-key cryptographic systems (RSA, ECC) widely used in digital communication protocols such as TLS, IPsec, VPNs, and secure messaging. Traditional systems face risks from "Harvest Now, Decrypt Later" attacks, compromising long-term confidentiality of sensitive data in finance, healthcare, government, and critical infrastructure. This paper proposes Quantum Shield, a comprehensive post-quantum secure framework for next-generation digital communication. It integrates NIST-standardized post-quantum algorithms (ML-KEM for key encapsulation, ML-DSA and SLH-DSA for digital signatures) with hybrid crypto-agile designs, hardware acceleration support, and role-based access controls. The system ensures quantum-resistant key establishment, authentication, and end-to-end encryption while maintaining low latency and high throughput. Experimental evaluation on simulated network traffic demonstrates acceptable performance overhead, enhanced resistance to quantum attacks, improved traceability, and secure multi-party coordination. Quantum Shield bridges the gap between classical and quantum-safe infrastructures, fostering trust and compliance in an era of quantum threats.
The emergence of quantum computing poses an existential threat to classical cryptographic systems that form the backbone of contemporary digital security infrastructure. RSA, the most widely deployed public-key cryptosystem, relies on the computational hardness of integer factorization, a problem efficiently solvable by quantum computers using Shor's algorithm. This impending vulnerability has catalyzed the development of post-quantum cryptographic alternatives designed to withstand both classical and quantum attacks. CRYSTALS-Kyber, standardized by NIST as ML-KEM, represents the forefront of latticebased key encapsulation mechanisms, offering quantum resistance through the Module Learning With Errors (MLWE) problem. This paper presents a comprehensive comparative analysis of RSA and Kyber, examining their mathematical foundations, security architectures, operational characteristics, and performance metrics across diverse computational environments. The study investigates the fundamental trade-offs between legacy systems optimized for classical threat models and emerging quantum-resistant algorithms designed for future-proof security. Through detailed analysis of key generation, encryption/encapsulation, decryption/decapsulation operations, and security guarantees, this research establishes the technical rationale behind NIST's selection of Kyber as the primary post-quantum key establishment mechanism. The findings demonstrate that while RSA maintains advantages in key size efficiency, Kyber's superior performance profile, quantum resilience, and robust security foundation position it as the essential successor for securing digital communications in the quantum era. This comprehensive study provides critical insights for organizations transitioning from classical to post-quantum cryptographic infrastructure
As the era of quantum computing approaches, the fundamental cryptographic primitives securing global communications face a paradigm shift. With the National Institute of Standards and Technology (NIST) finalizing new standards, the industry must urgently address the vulnerabilities of legacy systems. The imminent advent of CRQCs (Cryptographically Relevant Quantum Computers) poses an existential threat to the Public Key Infrastructure (PKI) underpinning the global digital economy. Classical algorithms such as RSA and ECC (Elliptic Curve Cryptography) are vulnerable to polynomial-time cryptanalysis via Shor’s algorithm. This study investigates the HNDL (Harvest Now, Decrypt Later) threat model and evaluates the resilience of NIST-standardized PQC (Post-Quantum Cryptography) algorithms: ML-KEM and ML-DSA. Utilizing a high-performance Fortinet networking environment, we experimentally validate that "Hybrid Mode" IPsec VPNs can achieve quantum resistance with negligible performance degradation, offering a viable migration path for enterprise infrastructure. Specifically, we benchmark the trade-offs between PQC’s larger key sizes and network latency, demonstrating that the overhead remains within acceptable operational thresholds. Implementing hybrid protocols provides a critical transition mechanism, allowing organizations to secure long-term data confidentiality against retrospective decryption while preserving interoperability with legacy systems.