Modeling Adversaries in a Logic for Security Protocol Analysis

Logics for security protocol analysis require the formalization of an adversary model that specifies the capabilities of adversaries. A common model is the Dolev-Yao model, which considers only adversaries that can compose and replay messages, and decipher them with known keys. The Dolev-Yao model is a useful abstraction, but it suffers from some drawbacks: it cannot handle the adversary knowing protocol-specific information, and it cannot handle probabilistic notions, such as the adversary attempting to guess the keys. We show how we can analyze security protocols under different adversary models by using a logic with a notion of algorithmic knowledge. Roughly speaking, adversaries are assumed to use algorithms to compute their knowledge; adversary capabilities are captured by suitable restrictions on the algorithms used. We show how we can model the standard Dolev-Yao adversary in this setting, and how we can capture more general capabilities including protocol-specific knowledge and guesses.Comment: 23 pages. A preliminary version appeared in the proceedings of FaSec'0

Pitfalls in Ultralightweight RFID Authentication Protocol

Radio frequency identification (RFID) is one of the most promising identification schemes in the field of pervasive systems. Non-line of sight capability makes RFID systems more protuberant than its contended systems. Since the RFID systems incorporate wireless medium, so there are some allied security threats and apprehensions from malicious adversaries. In order to make the system reliable and secure, numerous researchers have proposed ultralightweight mutual authentication protocols; which involve only simple bitwise logical operations (AND, XOR & OR etc.) to provide security. In this paper, we have analyzed the security vulnerabilities of state of the art ultralightweight RFID authentication protocol: RAPP. We have proposed three attacks (two DoS and one Desynchronization) in RAPP protocol and challenged its security claims.  Moreover, we have also highlighted some common pitfalls in ultralightweight authentication protocol designs. This will help as a sanity check, improve and longevity of ultralightweight authentication protocol designs