Advanced Encryption Standard (AES)

My implementation of AES 256-bit encryption written in pure Python! This features the ability to use ECB mode and CBC mode along with various types of input data.

ECB Mode

The simplest of the encryption modes is the Electronic Codebook (ECB) mode.

The message is divided into blocks, and each block is encrypted separately.

# A simple example of encrypting a string with ECB mode!

key = 0x000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f

aes = AES(key)
cyphertext = aes.encrypt('Hello World!')
plaintext = aes.decrypt(cyphertext) 

CBC Mode

In Cipher Block Chaining (CBC) mode, each block of plaintext is XORed with the previous ciphertext block before being encrypted. This can be denoted as:

Encryption: Ci = Ek(Pi xor C(i-1)) and C0 = IV

Decryption: Pi = Dk(Ci) xor C(i-1) and C0 = IV

# A simple example of encrypting bytes with CBC mode!

key = 0x000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
iv = 0x000102030405060708090a0b0c0d0e0f

aes = AES(key, iv)
cyphertext = aes.encrypt(b'Hello World!')
plaintext = aes.decrypt(cyphertext)