OpenSSL is an open source project that provides a robust, commercial-grade, and full-featured toolkit for the Transport Layer Security (TLS) and Secure Sockets Layer (SSL) protocols.
It is also a general-purpose cryptography library.
The toolkit is licensed under an Apache-style license, which basically means that you are free to get and use it for commercial and non-commercial purposes subject to some simple license conditions.
Please remember that export/import and/or use of strong cryptography software, providing cryptography hooks, or even just communicating technical details about cryptography software is illegal in some parts of the world.
So when you import this package to your country, re-distribute it from there or even just email technical suggestions or even source patches to the authors or other people you are strongly advised to pay close attention to any laws or regulations which apply to you.
OpenSSL is a a collaborative effort of a worldwide community of volunteers. We are always grateful to receive support for the project.
In addition to joining the community, you can make a direct donation to the project. Your contribution will help fund members of our development team. Significant sponsors have a say in the future direction of OpenSSL as well as acknowledgements and logo placements. We would like to take this opportunity to acknowledge those who have provided financial support.
For Windows: http://gnuwin32.sourceforge.net/packages/openssl.htm