John the Ripper

John the Ripper is a fast password cracker, currently available for many flavors of Unix, Windows, DOS, and OpenVMS. Its primary purpose is to detect weak Unix passwords. Besides several crypt(3) password hash types most commonly found on various Unix systems, supported out of the box are Windows LM hashes, plus lots of other hashes and ciphers.

John the Ripper is free and Open Source software, distributed primarily in source code form. It is available under the GNU General Public License (GPL) version 2 or later.

Key Features:

• Supports hundreds of hash and cipher types
• Multiple cracking modes: Wordlist, Incremental, External
• Custom cracking rules
• Detects weak password hashes
• CPU, GPU, and distributed cracking
• Highly optimized for performance