Your Turn: Add Encryption

Did You Know: Again, Stronger Together

As mentioned earlier, devices on a network need both encryption AND protection from malformed packets. This does not normally take many lines of code. Like the earlier example, both Sender and Receiver scripts need the encrypt/decrypt function (ascii_shift in our example).

def ascii_shift(key, text):
    result = ''
    for letter in text:
        ascii = ( ord(letter) + key - 32 ) % 94 + 32
        result = result + chr(ascii)
    return result

The Sender script also needs to encrypt the packet before sending:

        packet = ascii_shift(17, packet)

…and the Receiver needs to decrypt the packet after receiving:

        packet = ascii_shift(-17, packet)

In Python for computers (as opposed to MicroPython for the micro:bit), an encryption/decryption module would be imported. Instead of adding a comparatively weak encryption function, you’d import a module like PyCryptodome, Cryptography, or PyNaCl and use its stronger cryptography methods to encrypt and decrypt.