demo · v131

server readiness matrix

A reference for which TLS server software supports the hybrid keyshare today, what flag turns it on, and how to test it from the command line. Useful for the operations side of post-quantum migration planning.

support matrix (as of 2026-05)

serverversionX25519Kyber768config note
NGINX (with OpenSSL 3.2+ + oqs-provider)1.27+yesssl_ecdh_curve "X25519MLKEM768";
Caddy2.7+yesdefault once Go 1.23 ships
HAProxy (LibreSSL build)3.0+flagrequires ssl-default-bind-curves
Cloudflareedgeyesauto-enabled per zone
Google Cloud Load Balancerallyesauto
AWS ALB2024-Q3+yesopt-in via policy
node.js (built-in https)22.xflag--openssl-legacy-provider not allowed
node.js23.x+yesdefault
Apache (mod_ssl)2.4.59+flagSSLOpenSSLConfCmd Groups X25519MLKEM768

test it

Two commands for verifying your server actually accepts the hybrid keyshare:

# openssl s_client (OpenSSL 3.2+)
openssl s_client -connect example.com:443 -tls1_3 -groups X25519MLKEM768

# look in the response for:
# Negotiated TLS1.3 group: X25519MLKEM768
# Wireshark filter to find post-quantum handshakes
tls.handshake.extensions.supported_group == 0x11ec   # X25519MLKEM768 codepoint

see also

scenario focus

Select a scenario to focus its rendered example and summary.