This paper introduces PQConnect, a post-quantum end-to-end tunneling protocol that automatically protects all packets between clients that have installed PQConnect and servers that have installed and configured PQConnect.Like VPNs, PQConnect does not require any changes to higher-level protocols and application software.PQConnect adds cryptographic protection to unencrypted applications, works in concert with existing pre-quantum applications to add postquantum protection, and adds a second application-independent layer of defense to any applications that have begun to incorporate application-specific post-quantum protection.Unlike VPNs, PQConnect automatically creates end-to-end tunnels to any number of servers using automatic peer discovery, with no need for the client administrator to configure perserver information.Each server carries out a client-independent configuration step to publish an announcement that the server's name accepts PQConnect connections.Any PQConnect client connecting to that name efficiently finds this announcement, automatically establishes a post-quantum point-to-point IP tunnel to the server, and routes traffic for that name through that tunnel.The foundation of security in PQConnect is the server's longterm public key used to encrypt and authenticate all PQConnect packets.PQConnect makes a conservative choice of postquantum KEM for this public key.PQConnect also uses a smaller post-quantum KEM for forward secrecy, and elliptic curves to ensure pre-quantum security even in case of security failures in KEM design or KEM software.Security of the handshake component of PQConnect has been symbolically proven using Tamarin.
This paper introduces PQConnect, a post-quantum end-to-end tunneling protocol that automatically protects all packets between clients that have installed PQConnect and servers that have installed and configured PQConnect.Like VPNs, PQConnect does not require any changes to higher-level protocols and application software.PQConnect adds cryptographic protection to unencrypted applications, works in concert with existing pre-quantum applications to add postquantum protection, and adds a second application-independent layer of defense to any applications that have begun to incorporate application-specific post-quantum protection.Unlike VPNs, PQConnect automatically creates end-to-end tunnels to any number of servers using automatic peer discovery, with no need for the client administrator to configure perserver information.Each server carries out a client-independent configuration step to publish an announcement that the server's name accepts PQConnect connections.Any PQConnect client connecting to that name efficiently finds this announcement, automatically establishes a post-quantum point-to-point IP tunnel to the server, and routes traffic for that name through that tunnel.The foundation of security in PQConnect is the server's longterm public key used to encrypt and authenticate all PQConnect packets.PQConnect makes a conservative choice of postquantum KEM for this public key.PQConnect also uses a smaller post-quantum KEM for forward secrecy, and elliptic curves to ensure pre-quantum security even in case of security failures in KEM design or KEM software.Security of the handshake component of PQConnect has been symbolically proven using Tamarin.
Quantum computing threatens current public-key cryptography. New quantum-safe communication protocols are needed to address this threat. PQConnect is a tunnelling protocol designed for automated, end-to-end secure communication that resists quantum attacks while remaining compatible with existing infrastructure. It employs a hybrid handshake integrating classical and post-quantum primitives to establish shared keys. This thesis analyses PQConnect’s handshake, which uses a nested hybrid key exchange combining three schemes. It layers Classic McEliece (a code-based key encapsulation), X25519 (Curve25519 elliptic-curve Diffie–Hellman), and SNTRUP761 (Streamlined NTRU Prime) key encapsulations. These are being utilized as Key Encapsulation Mechanisms (KEMs). The layers are nested so that each inner exchange is concealed by outer layers, making any single layer difficult to break. The analysis details how each layer contributes to key establishment and how fresh ephemeral keys ensure forward secrecy. Additional PQConnect mechanisms are examined, including streaming verification of hand-shake data and DNS-based key distribution. Streaming verification processes large hand-shake records incrementally, reducing memory usage. For key distribution, PQConnect retrieves hashed server public keys via authenticated DNS records: a client fetches a hash of the server’s long-term key from DNS and verifies it before initiating the handshake, avoiding reliance on centralized certificates. A ratcheting key schedule derives new chain keys for each time epoch and per-packet encryption keys, limiting key exposure and extending forward secrecy beyond the initial handshake. For performance evaluation, packet-level traffic was captured using Wireshark for both PQConnect and traditional TLS sessions. Captured packets were analyzed to compare handshake flows and performance metrics such as packet size and total transmitted data. The results show that PQConnect introduces only a modest increase in packet sizes and overall data volume, with no significant latency overhead. Streaming verification and DNS-based lookup were confirmed to function correctly without noticeable delay. In conclusion, the study finds that PQConnect can establish quantum-secure tunnels with minimal performance penalty. Its hybrid handshake effectively integrates post-quantum primitives while maintaining compatibility with current infrastructure. DNS-based key distribution and streaming verification enhance trust and efficiency. The ratchet mechanism provides robust forward secrecy. These findings suggest that PQConnect is a practical and future-ready solution for secure tunnelling.
Quantum computing poses an immediate threat to VPN infrastructure through the "harvest now, decrypt later" attack model, where adversaries collect encrypted traffic today for future decryption with quantum computers. While existing VPN protocols await formal post-quantum standardization, practical protection is needed now. This paper presents a deployable solution for adding post-quantum security to WireGuard without modifying the protocol itself. Our approach leverages WireGuard's existing pre-shared key (PSK) mechanism, delivering quantum-resistant PSKs over channels protected by ML-KEM hybrid TLS 1.3. Through a carefully designed split-service architecture separating authentication from configuration management, we achieve both cryptographic and operational benefits. The authentication service handles client connections using post-quantum TLS, while the configuration service manages WireGuard settings with no direct network exposure, providing defense in depth. This architecture has been successfully deployed across ExpressVPN's global infrastructure, demonstrating its practicality at scale. The solution provides immediate quantum resistance with minimal performance impact (15-20ms additional connection establishment time, no impact on steady-state throughput), supports dynamic IP allocation and simplified key management, and can be implemented by engineering teams without deep cryptographic expertise. We provide detailed implementation guidance for deployments ranging from small (<1,000 users) to enterprise scale. Our work demonstrates that post-quantum WireGuard is achievable today using proven technologies and sound engineering principles, offering VPN providers a straightforward migration path to quantum resistance without abandoning existing WireGuard deployments.
The current VPN systems that use Classical Cryptography are becoming increasingly vulnerable to attacks on Quantum Computers. This paper examines the creation and implementation of a Quantum-Safe VPN solution that incorporates Post-Quantum Cryptography (PQC) via the Kyber 512 algorithm. The proposal includes a practical client/server implementation using WireGuard as the tunneling protocol and Tailscale for connectivity with an additional level of protection enabling the use of PQC for key exchange via the liboqs library. Selected performance metrics were determined (latency, handshake duration, CPU utilization, throughput) and compared with those of the Classical VPNs. The findings indicate that while PQC will add extra processing overhead (in particular, the Handshake process), it provides a significantly stable and secure channel for communications. Although throughput was less than with Classical VPNs, and CPU usage was increased, the PQC enabled VPN was found to provide acceptable reliability and produce zero packet losses. The results of this study have proven that integration of PQC in a VPN is achievable in real world applications and demonstrates the necessity for secure methods in future networking.
In this paper we present PQ-WireGuard, a post-quantum variant of the handshake in the WireGuard VPN protocol (NDSS 2017). Unlike most previous work on post-quantum security for real-world protocols, this variant does not only consider post-quantum confidentiality (or forward secrecy) but also post-quantum authentication. To achieve this, we replace the Diffie-Hellman-based handshake by a more generic approach only using key-encapsulation mechanisms (KEMs). We establish security of PQ-WireGuard, adapting the security proofs for WireGuard in the symbolic model and in the standard model to our construction. We then instantiate this generic construction with concrete post-quantum secure KEMs, which we carefully select to achieve high security and speed. We demonstrate competitiveness of PQ-WireGuard presenting extensive bench-marking results comparing to widely deployed VPN solutions.
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.
We present a layered and modular network architecture that combines Quantum Key Distribution (QKD) and Post-Quantum Cryptography (PQC) to provide scalable end-to-end security across long distance multi-hop, trusted-node quantum networks. To ensure interoperability and efficient practical deployment, hop-wise tunnels between physically secured nodes are protected by WireGuard with periodically rotated pre-shared keys sourced via the ETSI GS QKD 014 interface. On top, Rosenpass performs a PQC key exchange to establish an end-to-end data channel without modifying deployed QKD devices or network protocols. This dual-layer composition yields post-quantum forward secrecy and authenticity under practical assumptions. We implement the design using open-source components and validate and evaluate it in simulated and lab test-beds. Experiments show uninterrupted operation over multi-hop paths, low resource footprint and fail-safe mechanisms. We further discuss the design's compositional security, wherein the security of each individual component is preserved under their combination and outline migration paths for operators integrating QKD-aware overlays in existing infrastructures.