Public key encryption with cryptography

gistfile1.txt

import base64
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives.asymmetric import rsa
from cryptography.hazmat.primitives import serialization
from cryptography.hazmat.primitives.asymmetric import padding
from cryptography.hazmat.primitives import hashes


# Create Private Key
private_key = rsa.generate_private_key(
    public_exponent=65537,
    key_size=2048,
    backend=default_backend()
)

private_key_str = private_key.private_bytes(
    encoding=serialization.Encoding.PEM,
    format=serialization.PrivateFormat.PKCS8,
    encryption_algorithm=serialization.NoEncryption()
).decode("utf-8")

public_key_str = private_key.public_key().public_bytes(
    encoding=serialization.Encoding.PEM,
    format=serialization.PublicFormat.SubjectPublicKeyInfo
).decode("utf-8")

print("=========================== PRIVATE KEY ===========================")
print(private_key_str)
print("=========================== PUBLIC KEY ===========================")
print(public_key_str)

del(private_key)


# Load Public Key & Public key
public_key = serialization.load_pem_public_key(
    public_key_str.encode("utf-8"),
    backend=default_backend()
)

private_key = serialization.load_pem_private_key(
    private_key_str.encode("utf-8"),
    backend=default_backend(),
    password=None,
)

# Ciper & b64
cipher_bytes = public_key.encrypt(
    "All your base are belong to us".encode('utf-8'),
    padding.OAEP(
        mgf=padding.MGF1(algorithm=hashes.SHA256()),
        algorithm=hashes.SHA256(),
        label=None,
    )
)

b64_ciphertext = base64.b64encode(cipher_bytes)

del(cipher_bytes)

cipher_bytes = base64.b64decode(b64_ciphertext)

plaintext = private_key.decrypt(
    cipher_bytes,
    padding.OAEP(
        mgf=padding.MGF1(algorithm=hashes.SHA256()),
        algorithm=hashes.SHA256(),
        label=None
    )
)

print("=" * 79)
print(cipher_bytes)
print("-" * 79)
print(plaintext.decode("utf-8"))