  RFID (Radio Frequency Identification) is a powerful technology that, due to
its numerous advantages, is supposed to replace the various identification
systems such as barcodes or magnetic stripes in a short time. There are three
devices involved in an RFID protocol: a Reader, a Tag, and a back-end Database.
One of the key factors for the RFID technology is that, in order to be used on
large scale, the price of the Tags has to be cheap: it cannot be expensive
because who is supposed to use it would need a great amount of them,
furthermore, Tags must have very small dimensions. The low-cost nature of such
devices implies the impossibility to use standard cryptographic protocols on
them, furthermore, Ultra-Lightweight Tags even lack the necessary computational
power to generate random numbers. Many experts are trying to build secure
protocols that involve just simple bitwise logical operations for these Tags,
but, unfortunately, each of these protocols turned out to be vulnerable to some
serious attack after short time from publication. The need for a secure RFID
authentication protocol today seems more urgent than ever, because this
technology is already used for security purposes, such as electronic passports.
The challenge to build a secure protocol for Ultra-Lightweight RFID systems is
so hard that in several years no one has been able to build one. In this thesis
we analyze in great detail a recently proposed protocol for Ultra-Lightweight
RFID systems called SLAP, with the aim of finding new vulnerabilities. SLAP has
already been violated (along with a set of similar protocols) by Safkhani and
Bagheri, that have recently published a de-synchronization attack. At the end
of our analysis, we will propose an impersonification attack to the protocol,
along with a fix for our attack and some considerations on the attacks proposed
on this kind of protocols.
