Binary package “libapache2-mod-gnutls” in ubuntu bionic

Apache module for SSL and TLS encryption with GnuTLS

 mod_gnutls provides TLS encryption using the GnuTLS library. It's
 similar in purpose to mod_ssl, but doesn't use OpenSSL, and provides
 some additional features:
  * PKCS #11 access to server keys and certificates,
  * OpenPGP authentication, and
  * using Monkeysphere for client certificate validation.