LatticeScan: is this site quantum-safe?

Shows whether the site you are on uses post-quantum key exchange, graded from a scan of its public servers.

A grade on the toolbar icon tells you whether the website in the current tab protects its connections against a future quantum computer. The grade comes from a scan of the site's public servers. LatticeScan reads public Certificate Transparency logs to find every hostname a domain has certificates for, then opens a TLS 1.3 connection to each one offering only hybrid ML-KEM key exchange, the post-quantum method standardised by NIST in FIPS 203. A server that completes that handshake is quantum-safe. One that refuses it is not, and traffic to it can be recorded today and decrypted once a large quantum computer exists. A means every public server negotiates post-quantum key exchange. B means most do. C means modern TLS but classical key exchange on some or all servers. D and F mark older weaknesses as well. Click the icon for the numbers: how many public servers were reachable, how many are quantum-safe, when the scan ran, and a link to the full report listing every server. Sites that nobody has scanned yet show a question mark and a link to run a free scan. What leaves your browser: the hostname of the tab you are looking at, sent to latticescan.com to look up a stored result. Nothing else. No page content, no account, no identifiers. Answers are cached for ten minutes in session storage and discarded when the browser closes. The extension never scans anything itself; it only reads results that already exist. LatticeScan's method is published at latticescan.com/methodology and every result is signed.