AI summaryⓘ
The authors studied how ready websites are for future quantum computers, which can break current internet security methods like RSA and ECC. They checked over 32,000 domains to see what security protocols and encryption methods were used and found that while some newer protections are being adopted, many sites, especially important ones like banks and governments, still use older, vulnerable systems. Around half of the sites support a mix of classical and post-quantum encryption for key exchange, but none use post-quantum certificates to verify identities, leaving an important security step exposed. The authors conclude that fully protecting internet communication from quantum attacks needs updating both the encryption methods and the certificate systems together.
Quantum ComputingTLSPost-Quantum CryptographyRSAElliptic Curve CryptographyKey ExchangeCertificatesTLS 1.3Quantum AttacksQUIC
Abstract
The emergence of quantum computing presents a fundamental challenge to the security of current Internet communication systems. Transport Layer Security (TLS), which forms the backbone of secure web communication, predominantly relies on classical public-key cryptographic algorithms such as RSA and elliptic curve cryptography (ECC), both of which are susceptible to quantum attacks. This paper conducts a large scale empirical evaluation of post-quantum readiness across 32,011 domains, with a primary focus on real-world TLS deployments across diverse sectors by analysing negotiated TLS parameters, including protocol versions, cipher suites, key exchange mechanisms, and certificates. The results indicate that while modern protocols like TLS 1.3 and QUIC are gaining adoption, 15.70% of domains especially in critical sectors such as banking and government still rely on TLS 1.2. Furthermore, 49.3% of domains support hybrid post-quantum key exchange mechanisms (e.g., MLKEM768 with X25519), whereas 50.7% continue to use classical key exchange, reflecting partial transition. Notably, 0% adoption of hybrid post-quantum certificates was observed, leaving the authentication layer vulnerable to quantum-enabled attacks such as certificate forgery. The findings reveal uneven adoption of post-quantum mechanisms across sectors, where technology driven platforms are advancing more rapidly than legacy-dependent infrastructures. Overall, the study highlights that achieving complete quantum resilience requires a coordinated transition not only in key exchange mechanisms but also in certificate infrastructures. Without such comprehensive migration, Internet communication systems remain vulnerable to long-term threats, including Harvest-Now-Decrypt-Later (HNDL) attacks.