The emergence of commercial quantum computers is inevitable and only a matter of time given the rapid progress made by companies such as IBM, Google, and Microsoft. Commercialization of quantum computers threatens cur-rent encryption methods that have worked effectively up until now however, with the advent of Shor’s and Grover's algorithms (quantum algorithms) for breaking current encryption methods, this compromises confidentiality, integrity and au-thenticity. Securing communication channels must be a top priority, and since email is the most widely used communication method, it must be addressed first. QMail, a Quantum Secure Email Client Application (QSECA), is designed to withstand both classical and quantum-level attacks. It uses a hybrid architecture of both Quantum Key Distribution (QKD) for the session key (simulated) and Post-Quantum Cryptography (PQC) for authentication and metadata protection, innovating on top of existing QSECA. The prototype we have made features a user-friendly interface to choose between three levels of encryption, including OTP. Our results indicate that QMail supports end-to-end security and offers pro-tection against adversaries with quantum capabilities, within the scope of the sce-narios tested. We have established QMail as a foundation for a quantum-safe communication platform - a step towards secure communication in the era of 6G and quantum internet with scalability as a direction for future work.
The emergence of commercial quantum computers is inevitable and only a matter of time given the rapid progress made by companies such as IBM, Google, and Microsoft. Commercialization of quantum computers threatens cur-rent encryption methods that have worked effectively up until now however, with the advent of Shor’s and Grover's algorithms (quantum algorithms) for breaking current encryption methods, this compromises confidentiality, integrity and au-thenticity. Securing communication channels must be a top priority, and since email is the most widely used communication method, it must be addressed first. QMail, a Quantum Secure Email Client Application (QSECA), is designed to withstand both classical and quantum-level attacks. It uses a hybrid architecture of both Quantum Key Distribution (QKD) for the session key (simulated) and Post-Quantum Cryptography (PQC) for authentication and metadata protection, innovating on top of existing QSECA. The prototype we have made features a user-friendly interface to choose between three levels of encryption, including OTP. Our results indicate that QMail supports end-to-end security and offers pro-tection against adversaries with quantum capabilities, within the scope of the sce-narios tested. We have established QMail as a foundation for a quantum-safe communication platform - a step towards secure communication in the era of 6G and quantum internet with scalability as a direction for future work.
The emergence of commercial quantum computers is inevitable and only a matter of time given the rapid progress made by companies such as IBM, Google, and Microsoft. Commercialization of quantum computers threatens cur-rent encryption methods that have worked effectively up until now however, with the advent of Shor’s and Grover's algorithms (quantum algorithms) for breaking current encryption methods, this compromises confidentiality, integrity and au-thenticity. Securing communication channels must be a top priority, and since email is the most widely used communication method, it must be addressed first. QMail, a Quantum Secure Email Client Application (QSECA), is designed to withstand both classical and quantum-level attacks. It uses a hybrid architecture of both Quantum Key Distribution (QKD) for the session key and Post-Quantum Cryptography (PQC) for authentication and metadata protection, innovating on top of existing QSECA. The prototype we have made features a user-friendly interface to choose between three levels of encryption, including OTP. The re-sults we obtained show that QMail ensures end-to-end security and provides pro-tection against adversaries with quantum capabilities. The results we obtained show that QMail ensures end-to-end security and provides protection against ad-versaries with quantum capabilities. We have established QMail as a foundation for a scalable, quantum-safe communication platform which is a step towards secure communication in the era of 6G and quantum internet.
The rapid growth of digital communication has increased the need for highly secure email systems capable of protecting sensitive information from evolving cyber threats. Traditional encryption techniques such as RSA and ECC are becoming vulnerable due to advancements in quantum computing, which can potentially break conventional cryptographic algorithms. To address these challenges, this project proposes a Quantum Secure Email Client Application that integrates post-quantum cryptography (PQC) techniques to ensure end-to-end secure communication. The proposed system employs quantum-resistant encryption algorithms such as lattice-based cryptography, hash-based signatures, or code-based encryption to secure email content, attachments, and user authentication processes. The email client ensures that messages are encrypted before transmission and can only be decrypted by the intended recipient, thereby preventing unauthorized access, interception, and data leakage. Additionally, the system incorporates secure key exchange mechanisms resistant to quantum attacks, ensuring safe communication even in the presence of quantum adversaries. The user interface is designed to be simple and user-friendly, allowing seamless sending and receiving of secure emails without requiring deep technical knowledge. The application enhances confidentiality, integrity, and authentication in email communication, making it suitable for defense, banking, healthcare, and government sectors where data security is critical. By integrating quantum-safe cryptographic techniques, the system provides a future-ready solution that safeguards communication against both classical and quantum computing threats.
Though an evolution-like speed describes quantum computing, it serves as one of the threats to traditional cryptographic systems, especially concerning email communication. The Quantum Secure Email Client Application (QSECA) is introduced here as a strong enough solution for protecting email content against future potential quantum threats. QSECA provides security on email communications with quantum-resistant encryption mechanisms, among which the most sophisticated are the Quantum Key Distribution (QKD) protocols, thus ensuring confidentiality, integrity, and authenticity to the recipient. Digital signature, multi-factor authentication, and encryption key management raise protection against adversarial acts such as spoofing, phishing, and any unauthorized intrusion into confidential information. A very convenient user interface and compatibility with established email systems, accompanied by additional security features such as secure transmission protocols and status notifications, help to preserve communications. The future development of QKD systems considered scalability and secure long-distance communication through the satellite route, which would have a direct impact on global network security. Other future development pathways include hybridization with post-quantum cryptographic algorithms and the use of blockchain technology for guarantees regarding data integrity, supported with possible intrusion detection from machine learning or AI. Thus, being a futuristic solution for email security, QSECA provides a fertile ground for individuals and organizations to further develop countermeasures against quantum security threats. Moreover, the paper delves into future development concerning integration into regulatory compliance standards and enhanced privacy mechanisms to satisfy evolving global data protection messages.
The emergence of quantum computing poses a significant threat to classical cryptographic mechanisms such as RSA and Elliptic Curve Cryptography that are widely used to secure email communication. Traditional secure email systems rely on classical public-key infrastructure and therefore lack resilience against quantum attacks. This paper presents QuMail, a quantum-secure email client that integrates BB84-based Quantum Key Distribution (QKD) simulation, CRYSTALS-Kyber post-quantum cryptography (PQC), and blockchain-based audit logging within a unified architecture. The proposed system operates entirely at the application layer and remains compatible with existing email infrastructures using standard SMTP and IMAP protocols without requiring any server-side modification. A modular prototype was implemented using IBM Qiskit for quantum key generation and hybrid cryptographic techniques for secure message transmission. Experimental evaluation demonstrates an average latency of 120–180 ms for QKD key generation and 20–30 ms for Kyber-based encryption while maintaining minimal overhead for email transmission. The results demonstrate the feasibility of integrating quantum-resilient security mechanisms into existing email systems and highlight the potential of hybrid QKD–PQC architectures for next-generation secure communication platforms.
Email has long been a vital tool for personal and professional communication, but its security relies on traditional cryptographic algorithms that are expected to become vulnerable due to developments in quantum computing. The paper presents a secure application-layer email model compatible with existing frameworks, enhancing confidentiality using quantum-resistant methods. The system supports OAuth 2.0 and OpenID Connect, eliminating password-based authentication and improving access security while enabling integration with services like Gmail and Outlook. It uses symmetric encryption and a hybrid one-time pad–based key mechanism to simulate post-quantum secure keys. All encryption and decryption occur at the application layer, ensuring end-to-end security without modifying SMTP or IMAP, while maintaining compatibility with existing email systems.
Abstract The rise of quantum computing challenges the fundamental security of classical public-key cryptography, exposing email systems to harvest-now-decrypt-later (HNDL) attacks demanding the need for practical post-quantum solutions. We present QSecureMail, a quantum-key-distribution (QKD) supported email client featuring an Adaptive Security Policy Engine (ASPE) which dynamically selects encryption levels based on real-time key pool conditions. The system integrates ETSI GS QKD 014 infrastructure and incorporates a Hybrid QKD⊕PQC scheme (Level 3) that combines ML-KEM1024 (FIPS 203) with QKD-derived keys, along with an authenticated QKD-based one-time pad construction (Level 1). It also introduces a structured security attestation mechanism that enables transparent auditing of the security posture of each email. A reference implementation and evaluation show that the ASPE effectively manages key consumption across different security levels while maintaining practical performance. Overall, the results indicate that QSecureMail offers a feasible approach to deploying quantum-safe email over existing infrastructure.