Scenario 3 – RC4, my god, what are you doing?

RC4 was an encryption method briefly in vogue for its speed and simplicity. Anyone who designs or implements cryptography will know that those are two words that, while good when applied with other words, such as secure, thoroughly tested, and 300 rounds, are not great when they make up the core of a description.

RC4 can simply be described as PT XOR key = CT, the explanation to which is as follows:

• PT is your plaintext value

• Key is the secret value set to encrypt the values

• CT is the encrypted cipher text

XOR is exclusive or or bitwise addition, which is where two values are broken down into binary, overlayed, and where the numbers match, a 0 is returned, and where the numbers don't match, a 1 is given.

Setup

Setup can be easily achieved using the PyCrypto library and the following code:

From Crypto.Cipher import XOR
Cipher = XOR.new("iamakey")
msg = str(raw_input("message to send:")
cipher_text = cipher.encrypt(msg)
printcipher_text.encode('base64...