Caesar Cipher Program

A simple C++ console application that encrypts and decrypts text using the Caesar Cipher technique. It also includes a brute-force mode that tries all 25 possible shifts.

---

Features

• Encrypt — Shift letters forward by a chosen amount (1–25)
• Decrypt — Reverse the shift to recover the original message
• Brute Force — Display all 25 possible decryptions to crack an unknown cipher
• Input validation for both text (letters and spaces only) and shift value

---

How It Works

The Caesar Cipher is one of the oldest encryption techniques. Each letter in the text is shifted by a fixed number of positions in the alphabet.

Example (shift = 3):

Plain:   HELLO
Cipher:  KHOOR

---

Getting Started

Prerequisites

• A C++ compiler (e.g. g++, MSVC, MinGW)

Compile & Run

Using g++:

g++ -o caesar_cipher main.cpp
./caesar_cipher

Using MSVC (Visual Studio): Open the .cpp file in Visual Studio and run with Ctrl+F5.

Note: The code uses strcpy_s() which is a Microsoft-specific safe string function. If you're compiling on Linux/macOS with g++, replace strcpy_s(temp, text) with strcpy(temp, text).

---

Usage

Run the program and choose from the menu:

========================================
        CAESAR CIPHER PROGRAM          
========================================
  1. Encrypt                           
  2. Decrypt                           
  3. Brute Force                       
  4. Exit                              
========================================

1. Encrypt — Enter your text and a shift value. The encrypted text is displayed.
2. Decrypt — Enter the ciphertext and the same shift value to recover the original.
3. Brute Force — Enter a ciphertext to see all 25 possible decryptions.
4. Exit — Quit the program.

---

Example

Enter your choice: 1
Please Enter your text: Hello World
Please Enter number to shift: 4
Lipps Asvph

---

Limitations

• Accepts only alphabetic characters and spaces (no numbers or symbols)
• Maximum text length: 100 characters
• Shift value must be between 1 and 25

---

License

This project is open source and available under the MIT License.