A2U2: A stream cipher for printed electronics RFID tags

The design of hardware-oriented ciphers has an increasingly important role to play with emerging ubiquitous and pervasive computing devices, such as low cost passive Radio Frequency Identification (RFID) tags. The importance of such ciphers are further highlighted by novel manufacturing technologies, such as printed ink to develop extremely low cost RFID tags. Such developments bring new challenges, especially in terms of providing security, both to protect privacy as well as to enable applications dependent on security, such as e-tickets. In this paper we present a new stream cipher, A2U2, which uses principles of stream cipher design and approaches from block cipher design. Our lightweight cryptographic primitive has taken into consideration the extremely resource limited environment of printed ink tags, to develop a cipher that can be implemented with less than 300 gates, with the added benefit of high throughput provided by stream ciphers.