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. A mailing list on mcrypt is firstname.lastname@example.org Subscribe by visiting http://lists.hellug.gr/mailman/listinfo/mcrypt-dev ** ** 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. To enable the old dynamic loading behaviour use the --enable-dynamic-loading in the configure script. That way you can statically link the library and be 100% thread safe, since dlopen is not always thread safe. You can also enable dynamic loading and include some algorithms into the library. To include algorithms in the library use the --with-included-algos parameter in the configure script. Eg: ./configure --with-included-algos="rijndael-128 arcfour stream cbc cfb"