A Random Number Generator for Application in RFID Tags

Abstract

With the extensive use of RFID systems, the problem of information security becomes more and more critical. Cryptography can offer private communications between the RFID reader and tag by using elaborately generated cryptographic keys. These unpredictable and irreproducible secret keys determine the communication security, and they are normally created by a nondeterministic random number generator (RNG) [1]. In current RFID technologies, pseudo random number generators (PRNG) serve as random number sources. Owing to the mechanism of PRNGs, their output numbers show poor randomicity. These less random secret keys, with no doubt, reduce the security of data transmission. An oscillator-based Truly Random Number Generator application scheme in [2] provides a better solution. The TRNG exploits thermal noise of two resistors to modulate the edge of a sampling clock. The white noise based cryptographic keys prevent potential attackers to perform any effective prediction about the generator’s output even if the design is well-known. A major topic of this paper is to discuss how to realize a TRNG in the RFID tag system.