A Novel Trust Model for Unreliable Public Clouds
based on Domain Partition
PeiYun Zhang, Member, IEEE, Yang Kong
School of Mathematics and Computer Science
Anhui Normal University
Wuhu, Anhui 241003, China.
zpyanu@ahnu.edu.cn and yangkong2012@gmail.com
MengChu Zhou, Fellow, IEEE
Department of Electrical and Computer Engineering
New Jersey Institute of Technology
Newark, NJ 07102, USA.
zhou@njit.edu
Abstract—
Cloud computing has become an important
scientific computing and commercial application paradigm.
There are many computing resources and data in public
clouds, but there exist some threats caused by unreliable
services due to malicious providers or unacceptably poor
service performance. Traditional trust computing requires a
high overhead and thus decreases the performance of a
cloud system. To address such issues, this work proposes a
trust model by adopting trust certificate authority to
compute domain trust and global trust. The model
decreases computational complexity based on domain
partition. Sliding-windows are used to obtain updated
trust
values. Experimental results show that the proposed trust
model can achieve efficient and accurate trust computation.
Keywords.
Cloud computing; trust certificate authority; domain
partition; trust
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I.
I
NTRODUCTION
Cloud computing has experienced more than 10 years of
research and development. It brings convenience and simplicity
to users and service providers, such as through federation of
cloud providers [1]. More and more enterprises reduce
computing-related cost through service outsourcing with
maturity cloud computing technology.
Because of highly dynamic, distributed nature of cloud
services, trust computing is considered as one of the vital
challenges for
many high-security-demanding cloud
applications. According to the researches at University of
California at Berkeley, trust management and security are
ranked among the top 10 obstacles for adopting cloud
computing [2]. Unreliable cloud services may result in leakage
of user privacy data or easy-to-launch attacks. For example, a
software glitch at Dropbox (a USA-based cloud-storage
provider) temporarily allowed visitors to log in to any of its 25
million customers’ accounts using any password or none at all a
few years ago. Amazon’s Elastic Compute Cloud service
crashed during a system upgrade, knocking customers’ websites
off-line ranging from several hours to several days [3].
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978-1- 5090-4429- 0/17/$31.00 ©2017 IEEE
Traditional methods such Service-Level Agreement (SLA)
are inadequate for the trust management of complex cloud [4].
Customers facing problems identify a trustworthy cloud
provider solely on the basis of its SLA [5]. Providing new
secure and reliable trust management approaches in cloud has
been one of important foci of current cloud computing research.
II.
RELATED
WORKS
Since trust was introduced from sociology into the field of
computers in 1994, trust has brought new security mechanisms
to the computer field. Trust is important for service management
in cloud environments. Li et al. propose an adaptive and
attribute-based trust model [4]. Abdul-Rahman et al. propose
direct trust and indirect trust, and calculate trust through a model
and obtain trust transfer values among entities [6]. Shao et al.
propose a trust model for depicting indirect trust [7]. Kamvar et
al. put forward the EigenTrust model to compute global trust
based on local trust and transaction information of related nodes
[8], but the model does not differentiate direct trust and indirect
one, while the differentiation is very important for trust
computation. Xiong et al. present a PeerTrust model that uses
feedback trust values of nodes. The model has a strong ability to
resist malicious nodes, but convergence of their algorithm is
rather slow [9]. Santos et al. introduce trust into clouds to
improve security and reliability of cloud services [10]. Beth et al.
propose the concepts of trust relationship among entities and
compute trust transfer values by using a probability and
statistics-based method [11]. Yan et al. propose a trust transfer
model [12]. Park et al. build a secure trust computing model
based on a security protocol [13]. Xing et al. take trust into
cloud scheduling to improve reliability and successful rate of a
schedule [14]. Noor et al. propose a reputation-based trust
management framework that provides a set of functionalities to
deliver trust as a service [15]. The above models or methods
have problems such as large overhead or low performance.
Trust models can be divided into two categories depending
upon whether they rely on reliable third party or not. The
representative of the first category is based on public key
infrastructure (PKI) [16]. It can achieve strong transitive trust.
One or a group of reliable nodes issue trust certificates, store and
update trust values in real time. The trust model can compute
effective trust values, but it brings about great resource overhead.
The representative of the second category is based on a trust