Caesar Cryptography and Stream Cipher - README

A Python‑based implementation of Caesar Cipher encryption & decryption, including brute‑force attacks and frequency‑analysis methods. Supports English and German languages with both manual input and file-based input options.

Note: This README contains essential instructions and summaries.
For deeper technical explanations, full theory, and detailed flowcharts, please refer to the full project report.

1. Project Overview

This project implements:

• Caesar Cipher Encryption & Decryption
• Random Key Generation
• Manual Input and File-Based Input
• Brute-Force Decryption
• Frequency Analysis (Mathematical Attack)
• Support for English & German Languages
• Case‑Sensitive Encryption
• Automatic Output File Generation

The system functions like a stream cipher, encrypting each character sequentially using a shifting mechanism.

---

2. Features

Encryption

• Shifts characters based on a numeric key
• Case‑sensitive encryption
  • Example: 'A' → 'V', but 'a' → 'd'

Decryption

• Uses the provided key to reverse the shift

Brute Force Attack

• Tries all possible keys
• Writes results to Brute_Force_Output.txt

Frequency Analysis Attack

• Uses unigram, bigram, and trigram statistics
• Outputs results in Math_Analysis_Method_Output.txt

Dual Language Support

• English
• German

Flexible Input Options

• Manual message input
• File-based input using Original_data.txt

---

3. Technologies Used

• Programming Language: Python
• Cipher Type: Caesar Cipher (Stream-based shifting)
• Techniques: Brute-force search, frequency analysis
• Concepts: Character manipulation, modular arithmetic, file I/O

---

4. How to Run the Program

Method 1: Run Using Python

1. Open the folder Caeser_Cryptography
2. Open Command Prompt inside the folder
3. Run:

python main.py

Method 2: Run the Executable

Double‑click to run:

Ceaser_Cryptography.exe

Or run via Command Prompt:

Ceaser_Cryptography.exe

Full Documentation Available

The complete project report, including flowcharts, architecture diagrams, file‑level explanations, and mathematical background, is available here:
Caesar_Cryptography_Report.pdf