Data outsourcing is a growing business model offering services to individuals
and enterprises for processing and storing a huge amount of data. It is not
only economical but also promises higher availability, scalability, and more
effective quality of service than in-house solutions. Despite all its benefits,
data outsourcing raises serious security concerns for preserving data
confidentiality. There are solutions for preserving confidentiality of data
while supporting search on the data stored in outsourced environments. However,
such solutions do not support access policies to regulate access to a
particular subset of the stored data.
For complex user management, large enterprises employ Role-Based Access
Controls (RBAC) models for making access decisions based on the role in which a
user is active in. However, RBAC models cannot be deployed in outsourced
environments as they rely on trusted infrastructure in order to regulate access
to the data. The deployment of RBAC models may reveal private information about
sensitive data they aim to protect. In this paper, we aim at filling this gap
by proposing \textbf{ESPOONERBAC​} for enforcing RBAC policies in
outsourced environments. ESPOONERBAC​ enforces RBAC policies in an
encrypted manner where a curious service provider may learn a very limited
information about RBAC policies. We have implemented ESPOONERBAC​
and provided its performance evaluation showing a limited overhead, thus
confirming viability of our approach.Comment: The final version of this paper has been accepted for publication in
Elsevier Computers & Security 2013. arXiv admin note: text overlap with
arXiv:1306.482