fcrackzip is a third-party tool for cracking zip files passwords. Searches each zipfile given for encrypted files and tries to guess the password.
Let’s start by showing the help screen for the tool:

We created a file “Secret.txt” then zipped it with a password 123456, then we to crack it with fcrackzip command:

In this example we used the flag “–D” for dictionary attack and provided the rockyou.txt as the dictionary file.
Now another example were we can use the brute force method using the flag “-b” and no need to provide a dictionary file, we use the flag “-c” to provide a character, lowercase, uppercase letters, in our case the password is numbers so the syntax will be “-c ‘1’” also we used the flag “-v” for verbose information.

If we want to use the lowercase letters, we use the flag “-c ‘a’” and in the case of uppercase letters we use the flag “-c ‘A’”.