🔐 File Encryption / Decryption (Java)

A console-based Java application that encrypts or decrypts the contents of a text file using a simple Caesar Cipher algorithm. The program reads text from an input file, processes it based on the user's choice, and writes the result to a new output file.

---

📌 Features

• Encrypts the contents of a text file
• Decrypts an encrypted text file
• Uses a simple Caesar Cipher (Shift by 3)
• Reads data from an input file
• Writes processed data to a new output file
• Handles invalid user choices
• Uses efficient file handling with BufferedReader and BufferedWriter

---

🛠️ Technologies Used

• Java
• VS Code
• Git & GitHub

---

📂 Project Structure

Task-3-File-Encryption-Decryption
│
├── FileEncryptionDecryption.java
├── input.txt
├── encrypted.txt
├── decrypted.txt
├── README.md
├── .gitignore
└── Screenshots
    ├── input-file.png
    ├── encrypt-output.png
    ├── encrypted-file.png
    ├── decrypt-output.png
    └── decrypted-file.png

---

▶️ How to Run

1. Compile the program

javac FileEncryptionDecryption.java

2. Run the program

java FileEncryptionDecryption

3. Choose an option

1. Encrypt File
2. Decrypt File

4. Enter

• Input file name
• Output file name

The program will process the file and save the result.

---

🔒 Encryption Algorithm

This project uses a Caesar Cipher with a shift value of 3.

Example

Original Text

Hello Java

Encrypted Text

Khoor#Mdyd

Decrypted Text

Hello Java

---

📸 Screenshots

Input File

---

Encryption Process

Encrypted File

Decryption Process

Decrypted File

💡 Concepts Used

• File Handling
• BufferedReader
• BufferedWriter
• FileReader
• FileWriter
• StringBuilder
• String Manipulation
• Loops
• Conditional Statements
• Exception Handling
• Scanner Class

---

👨‍💻 Author

Sparsh Mehta

Project completed as part of the Cognifyz Technologies Java Development Internship (Level 2 - Task 3).