Cryptography is feasible on 4-Bit microcontrollers - A proof of concept

The RFID technology in combination with cryptographic algorithms and protocols is discussed widely as a promising solution against product counterfeiting. Usually the discussion is focussed on passive low-cost RFID-tags, which have harsh power constraints. 4-Bit microcontrollers have very low-power characteristics (5–60 μA) and are therefore an interesting platform for active and passive low-cost RFID-tags. To the best of our knowledge there are no implementations of cryptographic algorithms on a 4-bit microcontroller published so far. Therefore, the main contribution of this work is to demonstrate that cryptography is feasible on these ultra-constrained devices and to close this gap. We chose PRESENT [1] as the cryptographic algorithm, because contrary to many other ciphers, PRESENT uses a 4×4 S-Box. Our implementation draws a current of 6:7μA at a supply voltage of 1:8V and a frequency of 500 KHz and requires less than 200 ms for the processing of one data block.