Cryptography is Feasible on 4-Bit Microcontrollers - A Proof of Concept
Markus Vogt, Dipl.-Kfm. Axel Poschmann, Christof Paar
International IEEE Conference on RFID, Orlando, Florida, USA, April, 27 - 28, 2009.
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 uA) 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  as the cryptographic algorithm, because contrary to many other ciphers, PRESENT uses a 4x4 S-Box. Our implementation draws a current of 6.7 uA 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.[pdf] [bib]