Its primary purpose is to detect weak Unix passwords. But today it runs on fifteen different platforms. This password cracking tool is free and Open Source, initially developed for the Unix operating system. It uses wordlists/dictionary to crack many different types of hashes including MD5, SHA, etc. John the Ripper ( JTR) is a widely known and verified fast password cracker, available for Windows, DOS, BeOS, and OpenVMS and many flavours of Linux.
