Tests whether a domain supports post quantum hybrid key exchange (NIST FIPS 203 ML-KEM groups) over TLS 1.3, and whether Encrypted Client Hello (ECH) is advertised in DNS. Uses OpenSSL 3.5 to probe each group individually.
Quantum computers running Shor's algorithm can break classical elliptic-curve and RSA key exchange. The NIST Post Quantum Cryptography standardisation process produced ML-KEM (Module Lattice Key Encapsulation Mechanism, FIPS 203) as the primary quantum resistant KEM. Modern TLS implementations deploy it as a hybrid — combining classical X25519 with ML-KEM-768, so the handshake is safe under both classical and quantum adversaries.
The most widely deployed hybrid group is X25519MLKEM768, used by Chrome, Firefox, Cloudflare, and AWS CloudFront. This tool uses OpenSSL 3.5 to probe which groups your server actually supports.
ECH (RFC draft, HPKE based) encrypts the SNI in the TLS ClientHello so network observers cannot see which hostname a client is connecting to. It is signalled by an ech= parameter in the domain's DNS HTTPS record. Cloudflare and some other CDNs already support ECH.
References: NIST FIPS 203 (ML-KEM) · RFC 9180 (HPKE)