Libmcrypt is a thread-safe library providing a uniform interface to access several block and stream encryption algorithms. Check the manual page for more information on libmcrypt. Look at COPYING for license information and the individual files for more information. COPYING applies only for the mcrypt program and not the algorithms which most of them are public domain. ** ** Some hints: Since 2.5.4 libmcrypt does not use dynamic loading for the modules by default. All the algorithms and modes, are now included in the library.