import time
from time import perf_counter

from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import serialization, hashes
from cryptography.hazmat.primitives.asymmetric import ec


def generate_ecc_keypair():
    """Generates an elliptic curve key pair (private, public)."""
    private_key = ec.generate_private_key(
        curve=ec.SECP256K1(),
        backend=default_backend()
    )
    public_key = private_key.public_key()
    return private_key, public_key.public_bytes(
        encoding=serialization.Encoding.PEM,
        format=serialization.PublicFormat.SubjectPublicKeyInfo
    )


def encrypt_message(public_key, message):
    """Encrypts a message using the provided public key (ECC)."""
    public_key = serialization.load_pem_public_key(
        public_key,
        backend=default_backend()
    )

    # Omit complex symmetric encryption for demonstration
    ciphertext = message.encode('utf-8')  # Placeholder for actual encryption

    return ciphertext


def decrypt_message(private_key, ciphertext):
    """Decrypts a message using the provided private key (ECC)."""

    # Get the PEM-encoded representation of the private key
    private_key_pem = private_key.private_bytes(
        encoding=serialization.Encoding.PEM,
        format=serialization.PrivateFormat.PKCS8,
        encryption_algorithm=serialization.NoEncryption()
    )

    private_key = serialization.load_pem_private_key(
        private_key_pem,
        password=None,  # No password for demonstration
        backend=default_backend()
    )

    # Omit complex symmetric decryption for demonstration
    message = ciphertext.decode('utf-8')  # Placeholder for actual decryption

    return message


if __name__ == '__main__':
    private_key, public_key = generate_ecc_keypair()

    message = "This is a secret message!"  # You can change the message content here

    start_time = perf_counter()
    ciphertext = encrypt_message(public_key, message)
    encrypt_time = (perf_counter() - start_time) * 1000

    print("Encryption time:", encrypt_time, "ms") 

    start_time = perf_counter()
    decrypted_message = decrypt_message(private_key, ciphertext)
    decrypt_time = (perf_counter() - start_time) * 1000

    print("Decryption time:", decrypt_time, "ms") 

    print("Decrypted message:", decrypted_message)