Brute Force Attack: First, see this blog.

Dictionary words could also be altered in a randomized manner to check if they work this way

Dictionary Attack: In this mode, John the Ripper takes text string samples (usually from a file, called a wordlist, containing large number of words, phrases and possible passwords derived from previously leaked data dumps or breaches), encrypting it in the same format as the password being examined, and comparing the output to the encrypted string.

You can grab the source code and binaries there. The official website for John the Ripper is on Openwall. Of course, an enhanced “jumbo” community release has also been made available on the open-source GitHub repo. This version is the most used among penetration testers for cracking passwords.

Pro: It designed for use by professional pen testers, has additional features such as multilingual wordlists, performance optimizations and 64-bit architecture support.

GNU-licensed: it is free and open source (FOSS) version.

Document files (PDF, Microsoft Office’s, etc.).

Encrypted private keys (such as SSH, and cryptocurrency wallets).

User passwords of Unix flavors (Linux, Solaris, etc.).

John the Ripper supports hundreds of hash and cipher types, including for: Originally developed for the Unix operating system, it can run on many different platforms. Also, John is already installed on Kali Linux. John the Ripper is a part of the Rapid7 family of penetration testing/ hacking tools. It was designed to test password strength, brute-force encrypted (hashed) passwords, and crack passwords via dictionary attacks. John the Ripper is a free password cracking software tool.

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