Rita Alexandra Rodrigues Prates
Proof of Timely-Retrievability for Storage Systems at the Edge
Tese submetida para provas de mestrado em Engenharia
Informática e de Computadores Instituto Superior
Técnico, Universidade de Lisboa.
Edge computing is a model that places servers close to the edge of the
network, in order to assist applications that run in
resource-constrained devices. Edge servers may be used to store files
such that clients can access data with low-latency. Yet, as the
capacity of edge nodes is limited, providers of edge storage may be
tempted to oversell their capacity and to hide this behavior by
fetching, on-demand, data from the cloud instead of serving it with
the required low latency.
In this thesis, we study techniques that have been proposed in the
literature that can help in detect- ing this type of misbehavior, and
design and implement a new proof of storage to detect this rational
behavior. Our Proof of Timely-Retrievability (PoTR) aims to assess
whether a storage node at the edge is able to retrieve a data object
with a latency smaller than some specified threshold delta. We leverage
the availability of Trusted Execution Environments (TEEs), more
precisely Intel SGX, to ensure that the proof is produced by the fog
node being audited and to reduce the communication between the auditor
and the audited node. Our proof is issued in response to a challenge:
we describe how a challenge may be designed and configured, so that a
PoTR is obtained. We have evaluated our design experimentally, and we
show that the auditor is able to distinguish a fog node that respects
the target limit on data access latency delta from a fog node that does
- Proof of Timely-Retrievability for Storage Systems at
- Rita Alexandra Rodrigues Prates
- MSc Thesis. Instituto Superior Técnico,
Universidade de Lisboa.
- November 2021.
- Available BibTeX, MSC Thesis, and extended abstract, and
- Prova de Resposta Pontual no Acesso ao Armazenamento
Contratado na Periferia da Rede.
- R. Prates,
C. Correia, M. Correia, and L. Rodrigues
- Actas do décimo
segundo Simpósio de Informática (Inforum), Lisboa,
Portugal, Sep. 2021.
- Available BibTeX, extended report