Tesis doctoral de Joan MeliÁ Seguí
This dissertation deals with security concerns regarding low-cost radio frequency identification (rfid) communications. Rfid systems are composed by tags (also known as electronic labels) storing an identification sequence which can be wirelessly retrieved by an interrogator, and transmitted to the network through middlewares and information systems. Low-cost rfid integrates different technologies, regarding the resource constrained characteristic (thus, reduced cost) of the rfid tags. the main example of low-cost rfid is the electronic product code class 1 generation 2 (epc gen2) technology, which is designed to balance cost and functionality. The development of epc gen2 tags faces, in fact, several challenging constraints such as cost, compatibility regulations, power consumption, and performance requirements. As a consequence, the computational capabilities of epc gen2 tags are very simple. In this sense, the epc gen2 specification only considers two basic on board security features: pseudo-random number generators (prngs) and password-protected operations. The pseudo-randomness offered by on-board prngs is, indeed, used to protect the password-protected operations. Prngs are also used as an anti-collision mechanism for inventorying processes, and to acknowledge other gen2 specific operations (e.G., Memory writing, decommission of tags, and self-destruction). Prngs are, therefore, the crucial components that guarantee gen2 security. cryptographic suitable prng designs must satisfy unpredictability characteristics. For example, an external adversary who eavesdrops the communication cannot compute the prng internal state, even if many outputs of the generator have been observed. The adversary cannot either compute the next sequence, even if many other previous sequences have been observed. If the adversary can observe, or even manipulate, the input samples that are fed by a prng, but its internal state is not known, the adversary must not be able to compute the next sequence. Finally, if the adversary has somehow learned the internal state of the prng, but the input samples that are fed in cannot be observed, then the adversary should not figure out the internal state of the prng after the re-keying operation. Most of these characteristics are, in fact, required by the epc gen2 specification. hence, the use of weak prng designs that allow the predictability of the outgoing sequences introduces important security aws in epc gen2 communications. This dissertation includes the following points: in the first part, we present the main parameters of the epc gen2 technology, for both the communications interface and hardware characteristics. A complete state of the art on prngs and stream ciphers is introduced, with special emphasis to rfid and resource-constrained specific designs. the background obtained in this part gives us the framework to focus into the security analysis of rfid based on prngs. The second part of the document deepens on the analysis of prngs for rfid. We demonstrate the likelihood to predict a novel prng proposal based on a linearity vulnerability, and we also demonstrate statistical deviations on prngs from commercial rfid tags. The work presented in this part implies a lack of security in the communications of rfid systems. in the third part of this dissertation we propose a novel prng scheme for rfid, improving the state of the art for resource-constrained lowcost devices. Our proposal solves the linearity problem found in the analysis section, and is designed following the restrictions applying the low-cost rfid technology. A logical description and a hardware implementation are provided to test its suitability to the low-cost rfid technology. finally, the fourth and last part of this work presents an evaluation of our proposed prng based on four parameters: statistical behavior, security, hardware complexity and power consumption. The main interest is to demonstrate the hardware feasibility of our proposal to the epc gen2 technology, while providing a secure enough communication link. the contribution of this dissertation is the improvement of the state of the art on security in rfid epc gen2 technology. With the knowledge obtained from the analysis of commercial epc gen2 tags, and the evaluation of scientific proposals, we have been able to propose a new prng design compatible with the hardware and statistical epc gen2 requirements, and with improved security properties. We can conclude that our work leads to new design paradigms and recommendations for the security in low-cost rfid, and particularly for the epc gen2 technology. keywords: low-cost rfid, epc gen2, prng, lightweight security, attack implementation, empirical analysis, multiple polynomial, logical gates, power consumption.
Datos académicos de la tesis doctoral «Lightweigth prng for low-cost passive rfid security improvement«
- Título de la tesis: Lightweigth prng for low-cost passive rfid security improvement
- Autor: Joan MeliÁ Seguí
- Universidad: Oberta de catalunya
- Fecha de lectura de la tesis: 12/04/2011
Dirección y tribunal
- Director de la tesis
- Joaquin Garcia Alfaro
- Tribunal
- Presidente del tribunal: josep Domingo ferrer
- david Megías jiménez (vocal)
- (vocal)
- (vocal)