Lightweight Cryptography for Passive RFID Tags

In 2011, we are entering a decade where Radio Frequency IDentification (RFID) systems will become ubiquitous, slowly but surely replacing its old ancestor: the barcode. With the RFID technology come many advantages such as faster retailing, continuous control along the supply chain, real-time monitoring and localization of items, etc. However, all these benefits come to the condition of secure systems, especially in sensitive application areas such as military, finance, pharmaceutics, etc. Additionally, the privacy aspect involved with this technology could become a major issue in the perspective of a global adoption. In the past few years, an increasing number of researchers concentrates their efforts into providing secure solutions for RFID systems. After several attempts to integrate traditional cryptographic primitives into small, embedded, and extremely resource constrained devices, the results were mostly unsatisfactory. As a conclusion, a new branch of cryptography, commonly called Lightweight Cryptography, emerged to address the issues of these tiny ubiquitous devices.
This Thesis presents a comprehensive engineering to lightweight cryptography,
proposes a classification and explores its various ramifications by giving key examples in each of them. We select two of these branches, ultralightweight cryptography and symmetric-key cryptography, and propose a cryptographic
primitive in each of them. In the case of symmetric-key cryptography, we propose a stream cipher that has a footprint among the smallest in the published literature and aims at being implemented on printed electronics RFID
tags.
Then, we compare different cryptographic primitives based on their key parameters: throughput, area, power consumption and level of security. Our
main concern is the integrability of these selected primitives into real passive
RFID tags. Therefore, in order to go beyond a comparison of the different parameters, we propose a metric that combines all their characteristics into one
single value. This metric also has the advantage of being customizable, depending on the requirement of an integrator for a particular application.
Finally, we conclude that the research for finding robust cryptographic primitive
in the branch of lightweight cryptography still has some nice days ahead, and that providing a secure cryptosystem for printed electronics RFID tags remains an open research topic.