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<p align="center"> <img width="460" height="300" src="https://raw.githubusercontent.com/ctz/rustls/main/admin/rustls-logo-web.png"> </p> <p align="center"> Rustls is a modern TLS library written in Rust. It's pronounced 'rustles'. It uses <a href = "https://github.com/briansmith/ring"><em>ring</em></a> for cryptography and <a href = "https://github.com/briansmith/webpki">libwebpki</a> for certificate verification. </p>

Status

Rustls is ready for use. There are no major breaking interface changes expected. Here's what I'm working on now.

If you'd like to help out, please see CONTRIBUTING.md.

Build Status Build Status Coverage Status (codecov.io) Documentation

Release history:

See OLDCHANGES.md for further change history.

Documentation

Lives here: https://docs.rs/rustls/

Approach

Rustls is a TLS library that aims to provide a good level of cryptographic security, requires no configuration to achieve that security, and provides no unsafe features or obsolete cryptography.

Current features

Possible future features

Non-features

The following things are broken, obsolete, badly designed, underspecified, dangerous and/or insane. Rustls does not support:

There are plenty of other libraries that provide these features should you need them.

Platform support

Rustls uses ring for implementing the cryptography in TLS. As a result, rustls only runs on platforms supported by ring. At the time of writing this means x86, x86-64, armv7, and aarch64.

Example code

There are two example programs which use mio to do asynchronous IO.

Client example program

The client example program is named tlsclient. The interface looks like:

Connects to the TLS server at hostname:PORT.  The default PORT
is 443.  By default, this reads a request from stdin (to EOF)
before making the connection.  --http replaces this with a
basic HTTP GET request for /.

If --cafile is not supplied, a built-in set of CA certificates
are used from the webpki-roots crate.

Usage:
  tlsclient [options] [--suite SUITE ...] [--proto PROTO ...] <hostname>
  tlsclient (--version | -v)
  tlsclient (--help | -h)

Options:
    -p, --port PORT     Connect to PORT [default: 443].
    --http              Send a basic HTTP GET request for /.
    --cafile CAFILE     Read root certificates from CAFILE.
    --auth-key KEY      Read client authentication key from KEY.
    --auth-certs CERTS  Read client authentication certificates from CERTS.
                        CERTS must match up with KEY.
    --protover VERSION  Disable default TLS version list, and use
                        VERSION instead.  May be used multiple times.
    --suite SUITE       Disable default cipher suite list, and use
                        SUITE instead.  May be used multiple times.
    --proto PROTOCOL    Send ALPN extension containing PROTOCOL.
                        May be used multiple times to offer several protocols.
    --cache CACHE       Save session cache to file CACHE.
    --no-tickets        Disable session ticket support.
    --no-sni            Disable server name indication support.
    --insecure          Disable certificate verification.
    --verbose           Emit log output.
    --mtu MTU           Limit outgoing messages to MTU bytes.
    --version, -v       Show tool version.
    --help, -h          Show this screen.

Some sample runs:

$ cargo run --example tlsclient -- --http mozilla-modern.badssl.com
HTTP/1.1 200 OK
Server: nginx/1.6.2 (Ubuntu)
Date: Wed, 01 Jun 2016 18:44:00 GMT
Content-Type: text/html
Content-Length: 644
(...)

or

$ cargo run --example tlsclient -- --http expired.badssl.com
TLS error: WebPKIError(CertExpired)
Connection closed

Server example program

The server example program is named tlsserver. The interface looks like:

Runs a TLS server on :PORT.  The default PORT is 443.

`echo' mode means the server echoes received data on each connection.

`http' mode means the server blindly sends a HTTP response on each
connection.

`forward' means the server forwards plaintext to a connection made to
localhost:fport.

`--certs' names the full certificate chain, `--key' provides the
RSA private key.

Usage:
  tlsserver --certs CERTFILE --key KEYFILE [--suite SUITE ...] [--proto PROTO ...] [options] echo
  tlsserver --certs CERTFILE --key KEYFILE [--suite SUITE ...] [--proto PROTO ...] [options] http
  tlsserver --certs CERTFILE --key KEYFILE [--suite SUITE ...] [--proto PROTO ...] [options] forward <fport>
  tlsserver (--version | -v)
  tlsserver (--help | -h)

Options:
    -p, --port PORT     Listen on PORT [default: 443].
    --certs CERTFILE    Read server certificates from CERTFILE.
                        This should contain PEM-format certificates
                        in the right order (the first certificate should
                        certify KEYFILE, the last should be a root CA).
    --key KEYFILE       Read private key from KEYFILE.  This should be a RSA
                        private key or PKCS8-encoded private key, in PEM format.
    --ocsp OCSPFILE     Read DER-encoded OCSP response from OCSPFILE and staple
                        to certificate.  Optional.
    --auth CERTFILE     Enable client authentication, and accept certificates
                        signed by those roots provided in CERTFILE.
    --require-auth      Send a fatal alert if the client does not complete client
                        authentication.
    --resumption        Support session resumption.
    --tickets           Support tickets.
    --protover VERSION  Disable default TLS version list, and use
                        VERSION instead.  May be used multiple times.
    --suite SUITE       Disable default cipher suite list, and use
                        SUITE instead.  May be used multiple times.
    --proto PROTOCOL    Negotiate PROTOCOL using ALPN.
                        May be used multiple times.
    --verbose           Emit log output.
    --version, -v       Show tool version.
    --help, -h          Show this screen.

Here's a sample run; we start a TLS echo server, then connect to it with openssl and tlsclient:

$ cargo run --example tlsserver -- --certs test-ca/rsa/end.fullchain --key test-ca/rsa/end.rsa -p 8443 echo &
$ echo hello world | openssl s_client -ign_eof -quiet -connect localhost:8443
depth=2 CN = ponytown RSA CA
verify error:num=19:self signed certificate in certificate chain
hello world
^C
$ echo hello world | cargo run --example tlsclient -- --cafile test-ca/rsa/ca.cert -p 8443 localhost
hello world
^C

License

Rustls is distributed under the following three licenses:

These are included as LICENSE-APACHE, LICENSE-MIT and LICENSE-ISC respectively. You may use this software under the terms of any of these licenses, at your option.