Merge pull request #41 from haragam22/feature/encryptor-module

Add AES file encryptor/decryptor with password-based key

Author: devmalik7

Python/File_Encrytion_Decryption/Readme.md

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+
+# File_Encryption_Decryption
+
+A simple **AES-based file encryption and decryption module** in Python with **password-based key generation**.
+Supports encrypting and decrypting any file using a password entered from the command line.
+
+---
+
+## **Features**
+
+* AES encryption (CFB mode)
+* Password-based key derivation (PBKDF2HMAC + SHA256)
+* Modular code: `utils.py` handles encryption/decryption logic
+* CLI-based usage for files
+* Supports any file type (images, documents, etc.)
+
+---
+
+## **File Structure**
+
+```
+File_Encryption_Decryption/
+├── encryptor.py        # CLI tool to encrypt files
+├── decryptor.py        # CLI tool to decrypt files
+├── utils.py            # Encryption/decryption helper functions
+├── requirements.txt    # Dependencies
+└── sample.jpg          # Test file
+```
+
+---
+
+## **Installation**
+
+1. Clone the repository:
+
+```bash
+git clone https://github.com/haragam22/Code_Script
+cd Code_Script/Python/File_Encryption_Decryption
+```
+
+2. Create a virtual environment:
+
+```bash
+python -m venv venv
+```
+
+3. Activate the virtual environment:
+
+```bash
+# Windows
+venv\Scripts\activate
+
+# macOS/Linux
+source venv/bin/activate
+```
+
+4. Install dependencies:
+
+```bash
+pip install -r requirements.txt
+```
+
+---
+
+## **Usage**
+
+### **1. Encrypt a file**
+
+```bash
+python encryptor.py <file_path>
+```
+
+**Example:**
+
+```bash
+python encryptor.py sample.jpg
+```
+
+* Enter a password when prompted.
+* Creates an encrypted file: `sample.jpg.enc`.
+
+---
+
+### **2. Decrypt a file**
+
+```bash
+python decryptor.py <encrypted_file>
+```
+
+**Example:**
+
+```bash
+python decryptor.py sample.jpg.enc
+```
+
+* Enter the **same password** used for encryption.
+* Restores the original file: `sample.jpg`.
+
+---
+
+## **Module Functions (utils.py)**
+
+* `generate_key(password: str, salt: bytes = None) -> tuple[bytes, bytes]`
+  Generates a 256-bit AES key from a password using PBKDF2HMAC. Returns `(key, salt)`.
+
+* `encrypt_data(key: bytes, plaintext: bytes) -> bytes`
+  Encrypts bytes using AES (CFB mode) and prepends IV.
+
+* `decrypt_data(key: bytes, ciphertext: bytes) -> bytes`
+  Decrypts bytes using AES (CFB mode). Expects IV prepended.
+

Python/File_Encrytion_Decryption/decryptor.py

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+import sys
+from utils import generate_key, decrypt_data
+
+def main():
+    if len(sys.argv) != 2:
+        print("Usage: python decryptor.py <encrypted_file>")
+        sys.exit(1)
+
+    file_path = sys.argv[1]
+    password = input("Enter password: ")
+
+    with open(file_path, "rb") as f:
+        file_data = f.read()
+
+    # Extract salt and ciphertext
+    salt = file_data[:16]
+    ciphertext = file_data[16:]
+
+    # Generate key from password + salt
+    key, _ = generate_key(password, salt=salt)
+
+    try:
+        plaintext = decrypt_data(key, ciphertext)
+    except Exception as e:
+        print("Decryption failed! Wrong password or corrupted file.")
+        sys.exit(1)
+
+    # Save decrypted file
+    if file_path.endswith(".enc"):
+        out_file = file_path[:-4]
+    else:
+        out_file = file_path + ".dec"
+
+    with open(out_file, "wb") as f:
+        f.write(plaintext)
+
+    print(f"File decrypted successfully: {out_file}")
+
+if __name__ == "__main__":
+    main()

Python/File_Encrytion_Decryption/encryptor.py

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+import sys
+from utils import generate_key, encrypt_data
+import os
+
+def main():
+    if len(sys.argv) != 2:
+        print("Usage: python encryptor.py <file_path>")
+        sys.exit(1)
+
+    file_path = sys.argv[1]
+    password = input("Enter password: ")
+
+    # Read file
+    with open(file_path, "rb") as f:
+        data = f.read()
+
+    # Generate key
+    key, salt = generate_key(password)
+
+    # Encrypt
+    ciphertext = encrypt_data(key, data)
+
+    # Save encrypted file (prepend salt)
+    out_file = file_path + ".enc"
+    with open(out_file, "wb") as f:
+        f.write(salt + ciphertext)
+
+    print(f"File encrypted successfully: {out_file}")
+
+if __name__ == "__main__":
+    main()

Python/File_Encrytion_Decryption/requirements.txt

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+cryptography==46.0.0

Python/File_Encrytion_Decryption/sample.jpg

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+import os
+from cryptography.hazmat.primitives.kdf.pbkdf2 import PBKDF2HMAC
+from cryptography.hazmat.primitives import hashes
+from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
+from cryptography.hazmat.backends import default_backend
+
+def generate_key(password: str, salt: bytes = None) -> tuple[bytes, bytes]:
+    """
+    Generate AES key from password using PBKDF2HMAC.
+    Returns (key, salt)
+    """
+    if salt is None:
+        salt = os.urandom(16)  # Generate random salt
+    kdf = PBKDF2HMAC(
+        algorithm=hashes.SHA256(),
+        length=32,  # 256-bit AES key
+        salt=salt,
+        iterations=100_000,
+        backend=default_backend()
+    )
+    key = kdf.derive(password.encode())
+    return key, salt
+
+def encrypt_data(key: bytes, plaintext: bytes) -> bytes:
+    iv = os.urandom(16)  # AES block size
+    cipher = Cipher(algorithms.AES(key), modes.CFB(iv), backend=default_backend())
+    encryptor = cipher.encryptor()
+    ciphertext = encryptor.update(plaintext) + encryptor.finalize()
+    return iv + ciphertext  # prepend IV for decryption
+
+def decrypt_data(key: bytes, ciphertext: bytes) -> bytes:
+    iv = ciphertext[:16]
+    actual_ciphertext = ciphertext[16:]
+    cipher = Cipher(algorithms.AES(key), modes.CFB(iv), backend=default_backend())
+    decryptor = cipher.decryptor()
+    plaintext = decryptor.update(actual_ciphertext) + decryptor.finalize()
+    return plaintext