TU Darmstadt / ULB / TUbiblio

Long-Term Confidential Secret Sharing-Based Distributed Storage Systems

Traverso, Giulia (2019):
Long-Term Confidential Secret Sharing-Based Distributed Storage Systems.
Darmstadt, Technische Universität, FG Informatik, [Online-Edition: https://tuprints.ulb.tu-darmstadt.de/8762],
[Ph.D. Thesis]

Abstract

Secret sharing-based distributed storage systems can provide long-term protection of confidentiality and integrity of stored data. This is achieved by periodically refreshing the stored shares and by checking the validity of the generated shares through additional audit data. However, in most real-life environments (e.g. companies), this type of solution is not optimal for three main reasons. Firstly, the access rules of state of the art secret sharing-based distributed storage systems do not match the hierarchical organization in place in these environments. Secondly, data owners are not supported in selecting the most suitable storage servers while first setting up the system nor in maintaining it secure in the long term. Thirdly, state of the art approaches require computationally demanding and unpractical and expensive building blocks that do not scale well. In this thesis, we mitigate the above mentioned issues and contribute to the transition from theory to more practical secret sharing-based long-term secure distributed storage systems. Firstly, we show that distributed storage systems can be based on hierarchical secret sharing schemes by providing efficient and secure algorithms, whose access rules can be adapted to the hierarchical organization of a company and its future modifications. Secondly, we introduce a decision support system that helps data owners to set up and maintain a distributed storage system. More precisely, on the one hand, we support data owners in selecting the storage servers making up the distributed storage system. We do this by providing them with scores that reflect their actual performances, here used in a broad sense and not tied to a specific metric. These are the output of a novel performance scoring mechanism based on the behavioral model of rational agents as opposed to the classical good/bad model. On the other hand, we support data owners in choosing the right secret sharing scheme parameters given the performance figures of the storage servers and guide them in updating them accordingly with the updated performance figures so as to maintain the system secure in the long term. Thirdly, we introduce efficient and affordable distributed storage systems based on a trusted execution environment that correctly outsources the data and periodically computes valid shares. This way, less information-theoretically secure channels have to be established for confidentiality guarantees and more efficient primitives are used for the integrity safeguard of the data. We present a third-party privacy-preserving mechanism that protects the integrity of data by checking the validity of the shares.

Item Type: Ph.D. Thesis
Erschienen: 2019
Creators: Traverso, Giulia
Title: Long-Term Confidential Secret Sharing-Based Distributed Storage Systems
Language: English
Abstract:

Secret sharing-based distributed storage systems can provide long-term protection of confidentiality and integrity of stored data. This is achieved by periodically refreshing the stored shares and by checking the validity of the generated shares through additional audit data. However, in most real-life environments (e.g. companies), this type of solution is not optimal for three main reasons. Firstly, the access rules of state of the art secret sharing-based distributed storage systems do not match the hierarchical organization in place in these environments. Secondly, data owners are not supported in selecting the most suitable storage servers while first setting up the system nor in maintaining it secure in the long term. Thirdly, state of the art approaches require computationally demanding and unpractical and expensive building blocks that do not scale well. In this thesis, we mitigate the above mentioned issues and contribute to the transition from theory to more practical secret sharing-based long-term secure distributed storage systems. Firstly, we show that distributed storage systems can be based on hierarchical secret sharing schemes by providing efficient and secure algorithms, whose access rules can be adapted to the hierarchical organization of a company and its future modifications. Secondly, we introduce a decision support system that helps data owners to set up and maintain a distributed storage system. More precisely, on the one hand, we support data owners in selecting the storage servers making up the distributed storage system. We do this by providing them with scores that reflect their actual performances, here used in a broad sense and not tied to a specific metric. These are the output of a novel performance scoring mechanism based on the behavioral model of rational agents as opposed to the classical good/bad model. On the other hand, we support data owners in choosing the right secret sharing scheme parameters given the performance figures of the storage servers and guide them in updating them accordingly with the updated performance figures so as to maintain the system secure in the long term. Thirdly, we introduce efficient and affordable distributed storage systems based on a trusted execution environment that correctly outsources the data and periodically computes valid shares. This way, less information-theoretically secure channels have to be established for confidentiality guarantees and more efficient primitives are used for the integrity safeguard of the data. We present a third-party privacy-preserving mechanism that protects the integrity of data by checking the validity of the shares.

Place of Publication: Darmstadt
Uncontrolled Keywords: Solutions ; S6
Divisions: 20 Department of Computer Science
20 Department of Computer Science > Theoretical Computer Science - Cryptography and Computer Algebra
DFG-Collaborative Research Centres (incl. Transregio)
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres
Profile Areas
Profile Areas > Cybersecurity (CYSEC)
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 1119: CROSSING – Cryptography-Based Security Solutions: Enabling Trust in New and Next Generation Computing Environments
Date Deposited: 09 Jun 2019 19:55
Official URL: https://tuprints.ulb.tu-darmstadt.de/8762
URN: urn:nbn:de:tuda-tuprints-87622
Referees: Buchmann, Prof. Dr. Johannes and Safavi-Naini, Prof. Dr. Reihaneh
Refereed / Verteidigung / mdl. Prüfung: 24 April 2019
Alternative Abstract:
Alternative abstract Language
Verteilte Speichersysteme auf Secret-Sharing-Basis können anhaltenden Schutz in Vertraulichkeit und Integriät bieten. Dies kann durch regelmäßiges Aktualisieren der gespeicherten Anteile (Shares) sowie der Kontrolle ihrer Gültigkeit durch zusätzliche Audit Daten erreicht werden. Allerdings ist diese Art von Lösung in den meisten lebensnahen Situationen wie z.B. auch in grossen Unternehmen aus drei Gründen nicht optimal. Erstens stimmen die Zugriffsrechte der modernsten verteilten Speichersysteme auf Secret-Sharing-Basis nicht mit der hierarchischen Organisation in den Unternehmen überein. Zweitens bekommen die Datenbesitzer weder Unterstützung im Auswählen von passenden Speichersystemen noch im Erhalten der langfristigen Sicherheit eben dieser. Drittens fordern modernste Vorgehensweisen rechnerisch aufwändige und unpraktische sowie teure Bestandteile, die ökonomisch nicht sinnvoll sind. In dieser Doktorarbeit entschärfen wir die oben genannten Probleme und tragen zum Übergang von Theorie zur Praxis von verteilten Speichersystemen auf Secret-Sharing-Basis bei. Erstens zeigen wir, dass verteilte Speichersysteme auf hierarchischen Secret-Sharing-Verfahren gründen können, indem wir schnelle und sichere Algorithmen einführen, deren Zugriffsrechte an die hierarchischen Strukturen eines Unternehmens angepasst und in Zukunft auch verändert werden können. Zweitens stellen wir ein Entscheidungs-Unterstützungs-System vor, das Datenbesitzern dabei hilft, ein verteiltes Speichersystem aufzubauen und zu halten. Konkreter unterstützen wir Datenbesitzer auf der einen Seite dabei, den Speicherserver des verteilten Speichersystems auszuwählen. Dies machen wir durch gegenseitige Bewertung ihrer tatsächlichen Leistung. Das ist der Output eines neuen Bewertungsverfahrens, das auf dem Verhalten von rationalen Teilnehmern als statt auf dem klassischen gut/schlecht- Modell basiert. Auf der anderen Seite unterstützen wir Datenbesitzer beim Auswählen der besten Secret-Sharing- Verfahrensparameter unter Berücksichtigung der Bewertungen der Speicherserver und leiten sie beim Aktualisieren entsprechend der neuesten Bewertungsentwicklungen, um das System langfristig sicherzuhalten. Drittens stellen wir schnelle und finanziell tragbare verteilte Speichersysteme vor, die auf einem Trusted Execution Environment gründen, welches Daten korrekt auslagert und regelmäßig gültige Anteile berechnet. So müssen weniger Kanäle mit informationstheoretischer Sicherheit hergestellt werden, um die Vertraulichkeit zu garantieren und schnellere Verfahren werden benutzt, um vollständige Schutzmaßnahmen der Daten zu gewährleisten. Darüber hinaus stellen wir ein Third-party Verfahren zur Wahrung der Vertraulichkeit vor, welches den vollständigen langfristigen Schutz von Daten durch die Kontrolle der Gültigkeit der Anteile garantiert.German
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