/*! ## Current features * TLS1.2 and TLS1.3. * ECDSA, Ed25519 or RSA server authentication by clients. * ECDSA, Ed25519 or RSA server authentication by servers. * Forward secrecy using ECDHE; with curve25519, nistp256 or nistp384 curves. * AES128-GCM and AES256-GCM bulk encryption, with safe nonces. * ChaCha20-Poly1305 bulk encryption ([RFC7905](https://tools.ietf.org/html/rfc7905)). * ALPN support. * SNI support. * Tunable MTU to make TLS messages match size of underlying transport. * Optional use of vectored IO to minimise system calls. * TLS1.2 session resumption. * TLS1.2 resumption via tickets (RFC5077). * TLS1.3 resumption via tickets or session storage. * TLS1.3 0-RTT data for clients. * Client authentication by clients. * Client authentication by servers. * Extended master secret support (RFC7627). * Exporters (RFC5705). * OCSP stapling by servers. * SCT stapling by servers. * SCT verification by clients. ## Possible future features * PSK support. * OCSP verification by clients. * Certificate pinning. ## Non-features For reasons explained in the other sections of this manual, rustls does not and will not support: * SSL1, SSL2, SSL3, TLS1 or TLS1.1. * RC4. * DES or triple DES. * EXPORT ciphersuites. * MAC-then-encrypt ciphersuites. * Ciphersuites without forward secrecy. * Renegotiation. * Kerberos. * Compression. * Discrete-log Diffie-Hellman. * Automatic protocol version downgrade. */