Segurança de sistemas RFID com modulação aleatória.

Abstract

As other pervasive computing technologies (as facial recognition, mobile phones, etc.), the same ease-of-use and dissemination that make Radio-Frequency Identification (RFID) so revolutionary also opens the possibility for theft, covert tracking and behavioral profiling. In face of these vulnerabilities, the request for security and privacy are of major importance for the RFID. In this work we analyze a privacy scheme against passive adversaries based on random modulation of message in stead of classical cryptographic models for low cost wireless devices, such as an RFID tag. The main idea of this scheme is to deny the eavesdropper channel by reducing his signal-to-noise ratio, for instance. The analyzed scheme makes use of a pseudorandom generator to choose a basis of orthogonal modulation transmission. The seed of the PRG is the secret key generated from the public discussion in a noisy environment by protocol proposed by Chabanne and Fumaroli for low cost RFID tags. A contribution of this work was to analyze how much the canal of the adversary is wronged in relation to the canal of the authentic users. Assuming a scenario characterized by an adversary who has the number of receivers equals the number of bases used , a security flaw was identified. Seeking to resolve this flaw, another contribution of this work was to propose two new schemes. The first one uses two PRGs; one for random modulation and other to encrypt the message. The second scheme uses a single PRG to random modulation and encryption of the message.