Secure Sockets and Transport Layer Security

The OpenSSL Project is a collaborative effort to develop a robust,
commercial-grade, full-featured, and open source toolkit implementing
the Secure Sockets Layer (SSL v2/v3) and Transport Layer Security (TLS
v1) protocols with full-strength cryptography. The project is managed
by a worldwide community of volunteers that use the Internet to
communicate, plan, and develop the OpenSSL toolkit and its related
documentation.

Derivation and License

OpenSSL is based on the excellent SSLeay library developed by Eric A.
Young and Tim J. Hudson. The OpenSSL toolkit is licensed under an
Apache-style license, which basically means that you are free to get it
and to use it for commercial and noncommercial purposes.