OpenSSL is an open source software system that provides the following:
- Forensic-grade implementations of the most widely used hash functions.
- Symmetric cryptographic functions
- Asymmetric cryptographic function
- Certificate management functions
- A complete S/MIME implementation
- A complete SSL/TLS implementation
OpenSSL is interesting for forensic practitioners and developers because it provides a basic toolkit for building software, and because the higher-level certificate management functions give you an easy way to decode the contents of certificates that are used to secure computer systems.
This web page contains step-by-step instructions on using OpenSSL from the command line to perform specific tasks. There are a lot of online OpenSSL guides and we'll try to link to some of them from here. But this page is a handy reference just the same.