Privacy and security are vital for digital communications to protect sensitive information and enable free expression. In this paper we present CELS (Crystalline Encryption Layered Security), a security extension based on a hybrid cryptographic approach that layers post-quantum cryptography (PQC) on top of a messaging application, to provide end-to-end data security. We introduce two CELS protocols, one for shared key establishment and one for key retrieval. Our prototype implementation, Discord CELS is a Firefox sidebar extension that adds end-to-end message encryption to a Discord server channel with native webhooks. It uses CRYSTALS-Kyber-1024 compiled with Emscripten for key encapsulation along with AES-256 GCM and PBKDF2 from the Web Crypto API for data encryption. CELS is resistant to attacks by both classical and quantum computers. CELS enables users to protect their messages with end-to-end encryption from being viewed by the messaging application company when using their existing service such as Discord. It is adaptable to other messaging applications and has cross-device flexibility, subject to platform constraints. Extensive performance evaluations demonstrate that the prototype system achieves good efficiency with low overhead, making it a practical security enhancement.
Privacy and security are vital for digital communications to protect sensitive information and enable free expression. In this paper we present CELS (Crystalline Encryption Layered Security), a security extension based on a hybrid cryptographic approach that layers post-quantum cryptography (PQC) on top of a messaging application, to provide end-to-end data security. We introduce two CELS protocols, one for shared key establishment and one for key retrieval. Our prototype implementation, Discord CELS is a Firefox sidebar extension that adds end-to-end message encryption to a Discord server channel with native webhooks. It uses CRYSTALS-Kyber-1024 compiled with Emscripten for key encapsulation along with AES-256 GCM and PBKDF2 from the Web Crypto API for data encryption. CELS is resistant to attacks by both classical and quantum computers. CELS enables users to protect their messages with end-to-end encryption from being viewed by the messaging application company when using their existing service such as Discord. It is adaptable to other messaging applications and has cross-device flexibility, subject to platform constraints. Extensive performance evaluations demonstrate that the prototype system achieves good efficiency with low overhead, making it a practical security enhancement.
The emergence of quantum computing poses a fundamental threat to current public key cryptographic systems. This threat is necessitating a transition to quantum resistant cryptographic alternatives in all the applications. In this work, we present the implementation of a practical hybrid end-to-end encryption system that combines classical and post-quantum cryptographic primitives to achieve both security and efficiency. Our system employs CRYSTALS-Kyber, a NIST-standardized lattice-based key encapsulation mechanism, for quantum-safe key exchange, coupled with AES-256-GCM for efficient authenticated symmetric encryption and SHA-256 for deterministic key derivation. The architecture follows a zero-trust model where a relay server facilitates communication without accessing plaintext messages or cryptographic keys. All encryption and decryption operations occur exclusively at client endpoints. The system demonstrates that NIST standardized post-quantum cryptography can be effectively integrated into practical messaging systems with acceptable performance characteristics, offering protection against both classical and quantum adversaries. As our focus is on implementation rather than on novelty, we also provide an open-source implementation to facilitate reproducibility and further research in post quantum secure communication systems.
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.
Quantum computing poses a serious threat to traditional cryptography, with algorithms like RSA and ECC being vulnerable to attacks such as Shor’s algorithm. To address this, we propose a Post-Quantum Secure Chat Application using lattice-based cryptography, specifically CRYSTALS-Kyber for key exchange and CRYSTALS-Dilithium for digital signatures. The system provides end-to-end encryption with forward secrecy, ensuring message confidentiality, authenticity, and integrity. Mathematical formulations of key encapsulation, encryption, and signature verification are presented, alongside performance benchmarks. Experimental results show that the application achieves practical latency and throughput on real devices while resisting quantum attacks. This work demonstrates that integrating post-quantum algorithms into messaging platforms is both feasible and essential for secure future communication.
Recent advances in quantum computing have prompted urgent consideration for the migration of classical cryptographic systems to post-quantum alternatives. However, it is impossible to fully understand the impact that migrating to current Post-Quantum Cryptography (PQC) algorithms will have on various applications without actual implementation of quantum-resistant cryptography. On the other hand, PQC algorithms come with complexity and long processing times, which may impact the Quality of Service (QoS) of many applications. Therefore, PQC-based protocols with practical implementation across various applications are essential. This paper introduces a new framework for PQC standalone and PQC-AES (Advanced Encryption Standard) hybrid Public Key Encryption (PKE) protocols. Building on prior results, we focus on securing applications such as file transfer, video streaming, and chat-based communication using enhanced PQC-based protocols. The extended PQC-based protocols use a sequence number-based mechanism to effectively counter replay and man-in-the-middle attacks and mitigate standard cybersecurity attack vectors. Experimental evaluations examined encryption/decryption speeds, throughput, and processing overhead for these standalone PQC and PQC-AES hybrid schemes, benchmarking them against traditional AES-256 in an existing client-server environment. The results demonstrate that the new approaches achieve a significant balance between security and system performance compared to conventional deployments. Furthermore, the comprehensive security analysis confirms the robustness and effectiveness of the proposed PQC-based protocols across diverse attack scenarios. Notably, the PQC-AES hybrid protocol demonstrates greater efficiency for applications handling larger data volumes (e.g., 10–100 KB) with reduced latency, underscoring the practical necessity of carefully balancing security and operational efficiency in the post-quantum migration process.
Quantum computing presents a growing threat to classical encryption mechanisms such as RSA and ECC. This paper proposes a hybrid secure web browser architecture that integrates CRYSTALS-Kyber, a lattice-based post-quantum algorithm selected by NIST, for key encapsulation. The proposed hybrid cryptographic scheme combine classical and quantum-resistant algorithms is essential to ensure the continued confidentiality and integrity of digital communications in the future. Built with Kotlin, Spring Boot, and Java Swing, the browser establishes a secure channel using a TLS 1.3-inspired handshake, fortified with Kyber-based quantum-resilient key exchange. The system supports encrypted file and message transmission, provides real-time UI feedback, and simulates quantum attacks using Qiskit. The results demonstrate that the hybrid cryptographic approach enhances security by combining the strengths of both classical and post-quantum algorithms, while maintaining reasonable performance overhead.
Quantum computing is a potentially significant threat to classical cryptographic methods, commonly influenced for mobile communication security. In this paper, we propose one secure channel for private, personal mobile devices that are based not only on post-quantum cryptographically algorithm but also to secure communications in the quantum era. NIST-spec kemsKyber2 and Saber represent for irreplaceable session keys in communication against prospective quantum threats. The keys are periodically replaced in order to provide forward secrecy and to protect against an eventual compromise. In addition to the features of mobile platforms, the scheme employs a lightweight authentication protocol applied to lattice-based cryptography which has been shown to be secure and low resource overhead. Testing the proposed solution was practicable and wielded manageable results since it was performed on Android devices with an average key exchange latency of less than 250 milliseconds and a secure message delivery of below 500 milliseconds without compromising the AES-256 equivalence level of privacy. The engineers and software developers with the results from this study could safely claim that practically, it is indeed doable to transfer secure messages on mobile platforms in the post-quantum era and they’d have that same level of confidence with respect to the adoption of cipher suites based on post-quantum standards within any future communication systems.Keywords: Post-quantum cryptography, quantum-resistant encryption, key encapsulation mechanism (KEM), end-to-end encryption (E2EE), quantum key distribution (QKD), mobile communication security, lattice-based cryptography, publickey infrastructure (PKI), quantum computing threats.