🔐 Caesar Cipher Decryption Tool (C++)

This is a C++ program that performs decryption of Caesar cipher–encrypted text using manual key entry and character frequency analysis.

📂 Files

• caesar_ah.cpp: Main program that handles user input and decryption
• enc_library_ah.cpp: Custom Cipher class that handles all encryption/decryption logic

💡 Features

• Command-line interface for file input/output
• Decrypts Caesar cipher using custom key
• Frequency analysis to suggest possible key
• Displays sample output before writing to file

📌 Notes

• The Caesar cipher is a basic substitution cipher that shifts characters by a fixed number.
• This tool is designed to decrypt only uppercase alphabetic characters (A–Z).
• Punctuation, numbers, and lowercase letters are preserved but not decrypted.
• The decryption key must be entered manually; the program does not attempt brute-force cracking.
• Sample output is displayed before saving to allow the user to confirm correctness.
• This project was developed as part of a cybersecurity course to demonstrate classic cryptographic techniques and frequency analysis in action.

🛠 How to Run

Compile and run from terminal (using g++ or similar):

g++ caesar_ah.cpp -o decrypt
./decrypt encrypted.txt decrypted.txt