As Fast As A Rabbit — Light-weight Crypto For IoT

The methods we used for encryption, such as AES, are often not fit-of-purpose for devices which have limited storage and processing facilities. Thus newer methods are being investigated which are simpler to implement. Once of these is the Rabbit stream encryption method. With this we take a secret key and then generate an infinitely long cipher stream. The cipher key stream is then EX-OR’ed with the data stream. On the other side, we generate the same cipher key stream, and then EX-OR it with the inputting cipher stream, and thus recover the data stream. Nice and simple.

With this Bob must pass the secret key to Alice, for them both to create the same key stream. Along with this Bob needs to send the IV value used. If Eve is watching she will see the IV value, but will not know the secret key they have used:

Rabbit is thus one contender for a light weight stream cipher and was written by Martin Boesgaard, Mette Vesterager, Thomas Christensen and Erik Zenner. It creates a key stream from a 128-bit key and a 64-bit initialization vector (IV) [paper]. The IV makes sure that the same plaintext does not appear as the same ciphertext.