RSA Key Generation and Encryption with Cryptography Library

This code first generates a pair of RSA keys, then uses the public key to encrypt a message, and finally decrypts the message using the private key. It demonstrates how to handle key generation, encryption, and decryption using the cryptography library.

Technology Stack : cryptography, RSA, encryption, decryption, OAEP padding, SHA-256

Code Type : The type of code

Code Difficulty : Intermediate

                
                    
from cryptography.hazmat.primitives import hashes
from cryptography.hazmat.primitives.asymmetric import padding
from cryptography.hazmat.primitives import serialization
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives.serialization import load_pem_public_key, load_pem_private_key
import os

def generate_keys():
    # Generate a private key and a public key
    private_key = serialization.load_pem_private_key(
        open("private_key.pem", "wb").read(),
        password=None,
        backend=default_backend()
    )
    public_key = private_key.public_key()

    # Serialize the public key to PEM format
    public_key_pem = public_key.public_bytes(
        encoding=serialization.Encoding.PEM,
        format=serialization.PublicFormat.SubjectPublicKeyInfo,
        backend=default_backend()
    )

    with open("public_key.pem", "wb") as pem_file:
        pem_file.write(public_key_pem)

    return private_key, public_key

def encrypt_message(message, public_key):
    # Encrypt the message using the public key
    encrypted = public_key.encrypt(
        message,
        padding.OAEP(
            mgf=padding.MGF1(algorithm=hashes.SHA256()),
            algorithm=hashes.SHA256(),
            label=None
        )
    )
    return encrypted

def decrypt_message(encrypted_message, private_key):
    # Decrypt the message using the private key
    decrypted = private_key.decrypt(
        encrypted_message,
        padding.OAEP(
            mgf=padding.MGF1(algorithm=hashes.SHA256()),
            algorithm=hashes.SHA256(),
            label=None
        )
    )
    return decrypted

# Example usage
private_key, public_key = generate_keys()
message = b"Hello, World!"
encrypted_message = encrypt_message(message, public_key)
decrypted_message = decrypt_message(encrypted_message, private_key)

print(decrypted_message)