ShakalBhau0001/caesar-cipher-cryptanalysis-python

# 🔐 Caesar Cipher Cryptanalysis (Python) An educational **Python implementation of Caesar Cipher brute-force cryptanalysis.** This project demonstrates how classical encryption can be broken using **exhaustive search and simple English frequency scoring.** It is designed as a **learning and academic project** to understand why classical ciphers are insecure and how attackers analyze encrypted text — not as a real-world attack tool. ## 🧱 Project Structure caesar-cipher-cryptanalysis-python/ │ ├── app.py # Brute-force cryptanalysis tool (CLI based) ├── LICENSE # Project license └── README.md # Project documentation ## ✨ Features ### 🔍 Full Brute-Force Search - Tests all 25 possible Caesar shifts - Supports both: - `L` → Left shift - `R` → Right shift - Automatically evaluates all possible plaintext candidates ### 🧠 English Scoring System - Uses frequency-based heuristic scoring - Prioritizes common English letters (E, T, A, O, I, N, etc.) - Rewards spaces and readable structure - Ranks outputs automatically ### 📊 Auto-Ranked Results - Sorts plaintext candidates by likelihood - Displays top possible decryptions - Removes mirror duplicate results ### 🧮 Educational Focus - Demonstrates cryptanalysis workflow - Shows weakness of classical substitution ciphers - Reinforces modular arithmetic concepts - Clean and modular Python implementation ## 🛠 Technologies Used | Technology | Role | | ---------------------- | ----------------------------------- | | **Python 3** | Core programming language | | **ord() / chr()** | Character-to-ASCII conversion | | **Modular Arithmetic** | Circular alphabet shifting (`% 26`) | | **Heuristic Scoring** | English-likeness evaluation | ## 📌 Purpose of This Project This project is built to: - Understand Caesar Cipher weaknesses - Learn brute-force cryptanalysis - Explore basic frequency analysis concepts - Simulate attacker perspective ethically - Strengthen Python logic and modular design skills ## ▶️ How to Run ### 1️⃣ Clone the repository git clone https://github.com/ShakalBhau0001/caesar-cipher-cryptanalysis-python.git ### 2️⃣ Navigate to the project folder cd caesar-cipher-cryptanalysis-python ### 3️⃣ Run the program python app.py ### 4️⃣ Enter Cipher Text - Provide any Caesar-encrypted message - View automatically ranked possible plaintexts - Analyze shift and direction results ## 🔎 Example Enter Caesar cipher text: QEB NRFZH YOLTK CLU GRJMP LSBO QEB IXWV ALD Top Possible Plaintexts: Shift 3 | Dir R | Score 72 | THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG Shift 23 | Dir L | Score 72 | THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG ... ## ⚠️ Limitations - English scoring is heuristic-based (not statistical-grade) - Works only for Caesar Cipher - Not designed for real-world encrypted systems - CLI-based interaction only ## 🌟 Future Improvements - Implement full frequency distribution comparison - Add dictionary-based validation - Support file input - Add support for other classical ciphers - Convert into reusable Python module - Build GUI version ## ⚠️ Disclaimer This project is created **for educational and cybersecurity learning purposes only.** It demonstrates the inherent weakness of classical substitution ciphers such as Caesar Cipher. It must not be used for unauthorized access, malicious activity, or real-world security attacks. ## 🪪 Author