Graduate School and Research Center in Digital Sciences

StealthGuard: Proofs of retrievability with hidden watchdogs

Azraoui, Monir; Elkhiyaoui, Kaoutar; Molva, Refik; Önen, Melek

Research Report RR-13-280

This paper presents StealthGuard, an efficient and provably secure proof of retrievabillity (POR) scheme. StealthGuard makes use of a privacypreserving word search (WS) algorithm to search, as part of a POR query, for randomly-valued blocks called watchdogs that are inserted in the file before outsourcing. Thanks to the privacy-preserving features of the WS, neither the cloud provider nor a third party intruder can guess which watchdog is queried in each POR query. Similarly, the responses to POR queries are also obfuscated. Hence to answer correctly to every new set of POR queries, the cloud provider has to retain the file in its entirety. StealthGuard stands out from the earlier sentinelbased POR scheme proposed by Juels and Kaliski (JK), due to the use of WS and the support for an unlimited number of queries by StealthGuard. The paper also presents a formal security analysis of the protocol.

Document Bibtex

Title:StealthGuard: Proofs of retrievability with hidden watchdogs
Keywords:Proofs of Retrievability, Cloud Computing, Privacy-PreservingWord Search
Department:Digital Security
Eurecom ref:4338
Copyright: © EURECOM. Personal use of this material is permitted. The definitive version of this paper was published in Research Report RR-13-280 and is available at :
Bibtex: @techreport{EURECOM+4338, year = {2014}, title = {{S}tealth{G}uard: {P}roofs of retrievability with hidden watchdogs}, author = {{A}zraoui, {M}onir and {E}lkhiyaoui, {K}aoutar and {M}olva, {R}efik and {\"{O}}nen, {M}elek}, number = {EURECOM+4338}, month = {06}, institution = {Eurecom}, url = {},, }
See also: