Higher level access to ciphers and digests by name. New ciphers can be loaded at run time. The BIO io system which is a simple non-blocking IO abstraction. A simple stack. A Configuration loader that uses a format similar to MS .ini files.
Various companies hold various patents for various algorithms in various locations around the world.
The file contains some of the patents that we know about or are rumoured to exist. This is not a definitive list. RSA Security holds software patents on the RC5 algorithm. If you intend to use this cipher, you must contact RSA Security for licensing conditions. RC4 is a trademark of RSA Security, so use of this label should perhaps only be used with RSA Security's permission.