What are some examples of cryptography in Python?

What are some examples of cryptography in Python?

Python has several libraries for cryptography, such as PyCryptodome and cryptography. Would you like to see examples using one of these?

Yes, can you show me how to encrypt and decrypt a message using PyCryptodome?

Sure! Here's a simple example:

from Crypto.Cipher import AES
from Crypto.Util.Padding import pad, unpad
import os

key = os.urandom(16)  # Generate a random key
cipher = AES.new(key, AES.MODE_CBC)

# Encrypting a message
plaintext = b'This is a secret message.'
ct_bytes = cipher.encrypt(pad(plaintext, AES.block_size))

# Decrypting the message
cipher = AES.new(key, AES.MODE_CBC, cipher.iv)
pt = unpad(cipher.decrypt(ct_bytes), AES.block_size)
print(pt)

This code encrypts and decrypts a message using AES in CBC mode.

What if I want to use RSA instead?

For RSA, you can use the cryptography library. Here's a basic example:

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

# Generate RSA keys
private_key = rsa.generate_private_key(public_exponent=65537, key_size=2048, backend=default_backend())
public_key = private_key.public_key()

# Encrypting a message
message = b'Secure message'
ct = public_key.encrypt(message, padding.OAEP(mgf=padding.MGF1(algorithm=hashes.SHA256()), algorithm=hashes.SHA256(), label=None))

# Decrypting the message
pt = private_key.decrypt(ct, padding.OAEP(mgf=padding.MGF1(algorithm=hashes.SHA256()), algorithm=hashes.SHA256(), label=None))
print(pt)

This will encrypt and decrypt a message using RSA.