VPNs today protect our online connections using strong encryption algorithms, but the rise of quantum computing poses a potential threat to the cryptographic systems that secure these connections. While quantum computers powerful enough to break current encryption standards do not yet exist, the transition to post-quantum cryptography has already begun. Many internet users rely on virtual private networks (VPNs) to protect their privacy, but the security of these connections depends on a range of cryptographic mechanisms, some of which could be vulnerable to quantum attacks in the future. As a result, some VPN providers are already incorporating post-quantum standards to future-proof their services against potential threats. The quantum threat primarily targets the keys used in encryption, not the encryption itself. Most modern VPNs use a combination of symmetric and asymmetric encryption. Symmetric encryption, such as AES and ChaCha20-Poly1305, is used to protect data once a secure connection is established. These algorithms are considered relatively safe from quantum attacks, as they rely on shared secret keys that are difficult for quantum computers to break. The National Institute of Standards and Technology (NIST) still considers AES-128 to be sufficiently secure against quantum threats, with AES-192 and AES-256 offering even greater resistance. In contrast, asymmetric encryption methods like RSA, Diffie-Hellman, and elliptic curve cryptography are more vulnerable to quantum computing. These rely on mathematical problems that quantum algorithms, such as Shor’s algorithm, could solve efficiently. These methods are used in the initial phase of establishing a secure connection between a user’s device and a VPN server. If a sufficiently powerful quantum computer were to break these asymmetric systems, it could potentially recover the encryption keys used for symmetric encryption. This would allow an attacker to decrypt previously captured data, even if it was encrypted using quantum-resistant algorithms. To address this risk, the NIST has already introduced three post-quantum standards—ML-DSA and SLH-DSA for digital signatures, and ML-KEM for key exchange—in August 2024. These standards aim to replace current encryption methods vulnerable to quantum attacks. Several major VPN providers, including Mullvad, ExpressVPN, NordVPN, and Surfshark, have already begun integrating these post-quantum algorithms into their services. While the threat from quantum computing may still be distant, the need to protect long-term data confidentiality has driven the push toward post-quantum security. However, it is important to note that quantum-resistant encryption alone does not guarantee the overall security of a VPN, as other vulnerabilities, such as software flaws or malware, can also compromise a connection.