John the Ripper definition
First released in 1996, John the Ripper (JtR) is a password cracking tool originally produced for UNIX-based systems. It was designed to test password strength, brute-force encrypted (hashed) passwords, and crack passwords via dictionary attacks.
The tool comes in both GNU-licensed and proprietary (Pro) versions. An enhanced “jumbo” community release has also been made available on the open-source GitHub repo. The Pro version, designed for use by professional pen testers, has additional features such as bigger, multilingual wordlists, performance optimizations and 64-bit architecture support.
Some of the key features of the tool include offering multiple modes to speed up password cracking, automatically detecting the hashing algorithm used by the encrypted passwords, and the ease of running and configuring the tool making it a password cracking tool of choice for novices and professionals alike.