Useful Tools for Basic Cryptography

What is Cryptography?

Cryptography is the practice and study of hiding information. It is the art and science of keeping information secret and safe as much as possible. In the case of CTFs (WTF is a CTF?), the goal is usually to crack and decrypt the code or algorithm to reach the flag.

Here are some useful tools for cracking and breaking codes:

1. Quipquip

My personal favorite. Quipqiup is a fast and automated cryptogram solver. It can solve simple substitution ciphers, cryptoquips, patristocrats and more. The great thing about Quipquip is that you don't need to do anything grand, all you have to do is paste the encrypted text, hit Solve and wait for a few seconds. Quipquip will then try to find what encryption method was used and try to decrypt the text.

2. Rumkin

Rumkin has a page dedicated to simple text manipulation tools. This is extremely useful for those encrypted texts where you know what method was used but is too lazy to do it in paper-pencil style.

3. Cryptii

Just like Rumkin, but with some advanced encryption/decryption methods.

4. Crackstation, HashKiller, MD5 Online

While technically not decrypting, These sites are useful for finding hashes.

5. Barcode Reader and ZXing Decoder

Useful for reading Barcodes. QR codes, MaxiCodes, Data Matrix, etc.

6. John the Ripper

John the Ripper is a powerful free password cracking software tool. It is one of the most popular password testing and breaking programs as it combines a number of password crackers into one package, autodetects password hash types, and includes a customizable cracker.

As an example: Here I tried to crack a password-protected zip file named "sample.zip" using John The Ripper. It only took John The Ripper less than 3 seconds to crack it's password. Password was '"cryptography".