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CTF Cryptography

Created: 1/12/2026 Updated: 1/12/2026

Cryptography

Binary#

Binary basics : https://learn.sparkfun.com/tutorials/binary

Base64 basics : https://levelup.gitconnected.com/an-introduction-to-base64-encoding-716cdccc58ce

Historical encoding#

Cipher#

Caeser Cipher
Left shift 3

cat cipher.txt | tr "d-za-cD-ZA-C" "a-zA-Z"
bash

The tr command translates text from one set of characters to another, using a mapping. The first parameter to the tr command represents the input set of characters, and the second represents the output set of characters. Hence, if you provide parameters “abcd” and “pqrs”, and the input string to the tr command is “ac”, the output string will be “pr”.