Because it incorporates a variety of password crackers into one package, auto-detects password hash types, and offers a customizable cracker, it is one of the most widely used password testing and breaking tools. It was created for the Unix operating system, but it now runs on fifteen different platforms (eleven of which are architecture-specific versions of Unix, DOS, Win32, BeOS, and OpenVMS). John the Ripper is a free program for breaking passwords.
