Cryptography

Scrumbled and encrypted text

Whatever happen, google is your friend. There are a lot cryptography tools online. Some of good tool are made offline like OpenSSL.

Classic cipher / Simple decoder online tool

  1. https://quipqiup.com - quipqiup is a fast and automated cryptogram solver

  2. https://cryptii.com/ - All in one tool

  3. https://rot13.com/ - Rot 1 - 25 decryptor

  4. https://www.dcode.fr - All in one tool

Modern cryptography

  1. Cryptool

  2. John the Ripper

  3. Hashcat

OpenSSL cheatsheet

  • Decrypt a file using RSA private key

    • openssl rsautl -decrypt -inkey pub_priv.key -in ciphertext.file -out decrypted.file

  • Decrypt a file using AES-256-CBC and a keyfile

    • openssl enc -d -aes-256-cbc -in ciphertext.file -out cleartext.file -pass file:./key.file

  • Decrypt a file using AES-256-CBC

    • openssl enc -aes-256-cbc -d -in file.txt.enc -out file.txt

  • Decrypt a file using AES-256-CBC with base64 encoded

    • openssl enc -aes-256-cbc -d -a -in file.txt.enc -out file.txt

Cracking compressed file

  1. John the Ripper - john --wordlist=/usr/share/wordlists/rockyou.txt hash.txt

  2. fcrackzip - fcrackzip -D -u -p rockyou.txt filename.zip

Note: Sometimes there are some challenges that require you to develop your own decryptor for that particular challenge. Just make sure you have a good scripting/programming language to solve the challenges.

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