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Sonja Buchegger's Publications

Enabling Secure Secret Sharing in Distributed Online Social Networks
Zitatschlüssel	VABD-ESSSDOSN-09
Autor	Vu, Le Hung, and Aberer, Karl and Buchegger, Sonja and Datta, Anwitaman
Buchtitel	Proceedings of the Annual Computer Security Applications Conference (ACSAC '09)
Seiten	419–428
Jahr	2009
ISBN	978-0-7695-3919-5
ISSN	1063-9527
DOI	http://dx.doi.org/10.1109/ACSAC.2009.46
Ort	Honolulu, HI, USA
Monat	December
Zusammenfassung	We study a new application of threshold-based secret sharing in a distributed online social network (DOSN), where users need a means to back up and recover their private keys in a network of untrusted servers. Using a simple threshold-based secret sharing in such an environment is insufficiently secured since delegates keeping the secret shares may collude to steal the user's private keys. To mitigate this problem, we propose using different techniques to improve the system security: by selecting only the most reliable delegates for keeping these shares and further by encrypting the shares with passwords. We develop a mechanism to select the most reliable delegates based on an effective trust measure. Specifically, relationships among the secret owner, delegate candidates and their related friends are used to estimate the trustworthiness of a delegate. This trust measure minimizes the likelihood of the secret being stolen by an adversary and is shown to be effective against various collusive attacks. Extensive simulations show that the proposed trust-based delegate selection performs very well in highly vulnerable environments where the adversary controls many nodes with different distributions and even with spreading of infections in the network. In fact, the number of keys lost is very low under extremely pessimistic assumptions of the adversary model.