TLDR: Breaking Repeating-Key XOR Encryption

Date: 2020-07-05 Source: https://arpitbhayani.me/blogs/decipher-repeated-key-xor

Overview

Crack repeating-key XOR ciphers! Learn how to find the key length using Hamming distance and frequency analysis in this crypto challenge. Encryption is a process of encoding messages such that it can only be read and understood by the intended parties.

Key Points

• Encryption is a process of encoding messages such that it can only be read and understood by the intended parties.
• Encryption: A plain text is encrypted using an encryption key by performing a bitwise XOR operation on every character.
• Decryption: Decryption is a process of extracting the original message from the encrypted ciphertext given the encryption key.
• Finding the length of the Encryption Key: In order to recover the original text from the cipher, we first find the length of the encryption key used and then apply brute force with all possible keys of the estimated length and deduce the plain text.