# Data Encryption Standards: AES and RSA In the realm of cryptography, two standards have been widely adopted to secure electronic data: the Advanced Encryption Standard (AES) and the Rivest-Shamir-Adleman (RSA). ## AES - Symmetric Key Cryptography AES is a symmetric key encryption standard, meaning the same key is used for both encryption and decryption of data. It operates on blocks of data (128-bits) and uses cipher keys of lengths 128, 192, or 256 bits. AES is highly efficient in both hardware and software, making it a popular choice for performance-intensive applications. Here's a simple example of AES encryption using Python's `pycryptodome` library: ```python from Crypto.Cipher import AES from Crypto.Random import get_random_bytes data = b'This is a test.' key = get_random_bytes(16) # 128-bit key cipher = AES.new(key, AES.MODE_ECB) ciphertext = cipher.encrypt(data) ``` ## RSA - Asymmetric Key Cryptography Unlike AES, RSA is an asymmetric encryption standard. It uses two keys: a public key for encryption and a private key for decryption. This allows for secure communication without the need for the sender and receiver to share a common key. RSA's security derives from the computational difficulty of factoring large integers. Here's an example of RSA encryption using Python's `rsa` library: ```python import rsa (pub_key, priv_key) = rsa.newkeys(512) # Generate keys message = 'This is a test.' encrypted_message = rsa.encrypt(message.encode(), pub_key) ``` Note that RSA is computationally intensive and typically used to encrypt small amounts of data. For larger data, a common approach is to use RSA to securely share an AES key, then use AES to encrypt the actual data. Remember, AES and RSA are just tools in your cryptographic toolbox. The security of your system relies not only on the strength of these algorithms, but also on how they're implemented and used in context.