This section documents supplemental TLS (Transport Layer Security) functions that are available. TLS support is available when using Scalability Protocols with the <> transport, or when using WebSocket, either with the <> transport for Scalability Protocols, or combined with other HTTP capabilities. These functions depend on library support that is not included directly with _NNG_ however, so their presence will depend on whether this additional support was present and enabled with _libnng_ was built. Currently, this extra support can be provided by the https://tls.mbed.org[mbedTLS library].