XOR Cipher & Breaker Suite

Overview

This project explores the mechanics of Stream Ciphers and their vulnerabilities to Frequency Analysis. It includes:

1. The Cipher: A tool to encrypt files using XOR logic.
2. The Breaker: An automated tool that cracks single-byte XOR encryption using statistical analysis (frequency distribution).

Technical Concepts

• Bitwise Operations: Using XOR (^) for reversible encryption.
• File I/O: Reading/Writing raw binary streams in C.
• Cryptanalysis: Breaking encryption by analyzing byte frequency (detecting the most common character).

Usage

1. Compile the Cipher: gcc cipher.c -o cipher
2. Encrypt a file: cipher plain.txt hidden.bin
3. Compile the Breaker: gcc breaker.c -o breaker
4. Crack the code: breaker hidden.bin

Disclaimer

The XOR cipher (unless used as a One-Time Pad with a truly random key equal to the message length) is not cryptographically secure against modern attacks. This tool is intended for educational purposes or simple obfuscation, not for securing sensitive data.