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 as well as a full-strength general purpose cryptography library. For more information on OpenSSL, you can visit their website at www.openssl.org.
OpenSSL version
This documentation was written for OpenSSL 0.9.8b but may be usefull with other versions.