This paper presents a new 64-bit block cipher
with three key size options (64 bits, 96 bits and 128 bits), specifically designed for use in resource-constrained tiny devices, such as low-cost RFID tags and sensors. It’s designed by following the overall architecture of Crypton but with redesign and simplification of each component function to enable much compact implementation in both hardware and software. A simple hardware implementation of mCrypton is also presented to demonstrate its suitability to our target applications. Our prototype implementation based on the straightforward 1 cycle/round architecture just requires about 3500 to 4100 gates for both encryption and decryption, and about 2400 to 3000 gates for encryption only (under 0.13
m CMOS technology). The result shows that the hardware complexity of mCrypton is quite well within an economic range of low-cost RFID tags and sensors. A more compact implementation under development promises that further size reduction around 30% could be achievable using the 5 cycles/round architecture.