Examining selected randomness extractors for wireless sensor networks

Mgr. Ram Singh

Master's thesis

Abstract:

This thesis aims to implement and evaluate selected physical sources of randomness, as well as randomness extractors for the wireless sensor networks. The wireless sensor devices are ubiquitous and use cryptographic primitives to protect the control and data channels. The cryptographic key generation requires a truly random number generator. The sophisticated methods of truly random number generation are not feasible for resource-constrained wireless nodes. The physical sources of randomness based on variation in received signal strength and variation in resistance of photoresistor are implemented for wireless nodes, and performance is evaluated based on the min-entropy estimation of the output bit sequences of these sources. The physical sources of randomness are in general weak sources of randomness and contain a substantial amount of biasing and correlations in the output sequence. The randomness extractors are used to obtain desired entropy from these weak sources of randomness. The three randomness extractors deterministic, seeded, and multi-source are implemented and experimented with for randomness extraction from the two implemented physical sources of randomness. The implementation and performance comparison of these extractors based on the min-entropy estimation of the output sequence generated by the randomness extractors is also presented in this thesis.

Abstract:

This thesis aims to implement and evaluate selected physical sources of randomness, as well as randomness extractors for the wireless sensor networks. The wireless sensor devices are ubiquitous and use cryptographic primitives to protect the control and data channels. The cryptographic key generation requires a truly random number generator. The sophisticated methods of truly random number generation are not feasible for resource-constrained wireless nodes. The physical sources of randomness based on variation in received signal strength and variation in resistance of photoresistor are implemented for wireless nodes, and performance is evaluated based on the min-entropy estimation of the output bit sequences of these sources. The physical sources of randomness are in general weak sources of randomness and contain a substantial amount of biasing and correlations in the output sequence. The randomness extractors are used to obtain desired entropy from these weak sources of randomness. The three randomness extractors deterministic, seeded, and multi-source are implemented and experimented with for randomness extraction from the two implemented physical sources of randomness. The implementation and performance comparison of these extractors based on the min-entropy estimation of the output sequence generated by the randomness extractors is also presented in this thesis.

Keywords

Arduino, deterministic extractor, entropy estimation, entropy source, min-entropy, multi-source extractor, photoresistor, radio frequency(RF), randomness extractor, received signal strength (RSS), seeded extractor.

Language used: English

Date on which the thesis was submitted / produced: 13. 12. 2018

Thesis defence

• Date of defence: 31. 1. 2019
• Supervisor: prof. RNDr. Václav Matyáš, M.Sc.
• Reader: Mgr. Marek Sýs, Ph.D.

Masaryk University

Faculty of Informatics

Master programme / field:
Informatics / Information Technology Security (eng.)