ssl_session_timeout 1d;
ssl_session_cache shared:sslcache:10m;  # about 40000 sessions
ssl_session_tickets off;

ssl_dhparam dhparams.pem;

# intermediate configuration
ssl_protocols TLSv1.2 TLSv1.3;
ssl_ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384:DHE-RSA-CHACHA20-POLY1305;
ssl_prefer_server_ciphers off;
# HSTS (ngx_http_headers_module is required) (63072000 seconds)
#add_header Strict-Transport-Security "max-age=63072000" always;

# OCSP stapling
ssl_stapling on;
ssl_stapling_verify on;