Python Project With Source Code File Transfer System using Elliptic Curve Cryptography

Python Project With Source Code File Transfer System using Elliptic Curve Cryptography

File Transfer System using Elliptic Curve Cryptography (ECC) in Python is an ambitious project that combines cryptography, networking, and file handling. ECC is particularly interesting for this purpose due to its efficiency and suitability for resource-constrained environments, making it ideal for secure file transfers. Here’s a structured outline and implementation guide for such a project:

Project Outline

1. Key Generation and Exchange

   • Implement ECC key generation using a library like pycryptodome.
   • Exchange public keys securely between the client and server.

2. File Encryption and Decryption

   • Encrypt files using the AES (Advanced Encryption Standard) algorithm.
   • Use ECC to securely exchange the AES keys between the client and server.

3. Client-Server Communication

   • Establish a network connection between the client and server using sockets or a higher-level library like socketserver.
   • Define protocols for file transfer requests, acknowledgments, and errors.

4. Error Handling and Verification

   • Implement mechanisms to ensure data integrity and authenticity using ECC signatures.
   • Verify file integrity upon receipt using checksums or hash functions.

5. User Interface (Optional)

   • Develop a simple CLI or GUI for the client and server to interact with the file transfer system.

6. Logging and Debugging

   • Implement logging to capture events and errors during file transfer.
   • Include debugging tools to diagnose and resolve issues.

Implementation Steps

1. Setting Up the Environment

Start by setting up a virtual environment and installing necessary libraries:

$ mkdir file_transfer_system
$ cd file_transfer_system
$ python -m venv venv
$ source venv/bin/activate  # On Windows use `venv\Scripts\activate`
$ pip install pycryptodome

2. ECC Key Generation and Encryption

Generate ECC keys and use them to encrypt a symmetric key (AES key) for file encryption:

from Crypto.Cipher import AES
from Crypto.Random import get_random_bytes
from Crypto.PublicKey import ECC

# Generate ECC keys
key = ECC.generate(curve='P-256')
private_key = key.export_key(format='PEM')
public_key = key.public_key().export_key(format='PEM')

# Encrypt and decrypt with ECC keys
def encrypt_aes_key(aes_key, public_key):
    ecc_key = ECC.import_key(public_key)
    ecc_point = ecc_key.pointQ
    shared_key = ecc_point * aes_key
    return shared_key.x.to_bytes()

def decrypt_aes_key(shared_key, private_key):
    ecc_key = ECC.import_key(private_key)
    ecc_point = ecc_key.pointQ
    aes_key = shared_key * ecc_point
    return aes_key

# Generate AES key and encrypt it with ECC
aes_key = get_random_bytes(16)
encrypted_aes_key = encrypt_aes_key(int.from_bytes(aes_key, byteorder='big'), public_key)

3. File Encryption and Decryption

Encrypt and decrypt files using the AES algorithm:

def encrypt_file(file_path, aes_key):
    cipher = AES.new(aes_key, AES.MODE_EAX)
    with open(file_path, 'rb') as f:
        plaintext = f.read()
        ciphertext, tag = cipher.encrypt_and_digest(plaintext)
    with open(file_path + '.enc', 'wb') as f:
        [f.write(x) for x in (cipher.nonce, tag, ciphertext)]

def decrypt_file(file_path_enc, aes_key):
    with open(file_path_enc, 'rb') as f:
        nonce, tag, ciphertext = [f.read(x) for x in (16, 16, -1)]
        cipher = AES.new(aes_key, AES.MODE_EAX, nonce=nonce)
        plaintext = cipher.decrypt_and_verify(ciphertext, tag)
    with open(file_path_enc[:-4], 'wb') as f:
        f.write(plaintext)

# Example usage
encrypt_file('example.txt', aes_key)
decrypt_file('example.txt.enc', aes_key)

4. Client-Server Communication

Implement a basic client-server architecture using sockets

# Server side
import socket

def server():
    server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    server_socket.bind(('localhost', 12345))
    server_socket.listen(5)
    
    while True:
        client_socket, addr = server_socket.accept()
        print(f"Connection from {addr} established.")
        
        # Receive public key from client
        public_key = client_socket.recv(1024)
        
        # Send public key to client
        server_socket.send(public_key)
        
        # Perform file transfer with encryption and decryption
        
        client_socket.close()

# Client side
def client():
    client_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    client_socket.connect(('localhost', 12345))
    
    # Send public key to server
    client_socket.send(public_key)
    
    # Receive server's public key
    server_public_key = client_socket.recv(1024)
    
    # Perform file transfer with encryption and decryption
    
    client_socket.close()

# Example usage
server()
client()

5. Error Handling and Verification

Implement error handling and verification mechanisms to ensure secure and reliable file transfers using ECC signatures and checksums.

Conclusion

This project provides a solid foundation for building a File Transfer System using Elliptic Curve Cryptography in Python. Ensure to expand and refine each component based on your specific requirements and deployment environment. It not only enhances your Python skills but also provides practical experience in cryptography, networking, and system