Framework Modeling for User Privacy in Cloud Computing

This paper develops a user privacy framework in the cloud environment. Major user privacy issues are discussed in comparison with current solutions. The framework model for illustrating privacy in a cloud environment is provided. Different solutions for security, privacy, and trust concerns are discussed in detail.

Framework modeling for User privacy in cloud computing
Abstract
Many organizations around the world recognize the
vitality of cloud computing. However, there are
some concerns that make organizations reluctant in
adopting cloud computing. These include data
security, privacy, and trust issues. It is very
important that these issues are addressed to meet
client concerns and encourage the wider adoption of
cloud computing. This paper develops a user privacy
framework in the cloud environment. Major user
privacy issues are discussed in comparison with
current solutions.
I. INTRODUCTION
Cloud Computing is a modern architecture in which
resources are shared on the Internet in external physical
locations rather than on local servers. This new paradigm
has resulted in a major change in Information Technology
(IT) [1]. Moreover, it impacts positively on IT by delivering
cloud software and services [2]. However, one main
limitation of cloud computing is privacy. Privacy is a major
issue in cloud computing from both legal and user
perspective.
When organizations move their important data to the cloud,
they need high security and privacy measures to protect
their information. Privacy entails the protection and
appropriate use of user’s information [3]. To ensure privacy
in Cloud environments, clearly, state user requirement,
ensure accountability on data usage, specify limitations of
data collection and data usage, control the data visibility
and ensure data integrity and transparency [2].
In recent years, different techniques have been introduced
to store sensitive data. One way is to upload data into the
cloud. However, users have concerns about the privacy of
their sensitive data. Besides that, users have less control of
their data.
Privacy issues become more challenging in Cloud
Computing because cloud providers are authorized to
access all or some of the data. Also, the huge number of
users in cloud computing increase possibilities of data
breaches and thus privacy issues.
Cloud providers are required to ensure that users’ data
are protected properly. Some data protection techniques
include data segmentation, encryption, processing
encrypted data, obfuscation, sticky policy, trusted platform
module, and trusted third party mediator [3]. The
approaches include data-centric, user-centric, and hybrid
techniques [4].
A. Research Problem
Privacy is an important right for everyone in the
world. In IT privacy means secure and protect user
information. However, the rapid growth of IT and
computers bring about the challenge of data
protection. Most websites have their own legislation,
policies, and standards to manage the users’
information, and reach the users’ trust. Cloud
Computing should prioritize privacy because it hosts
confidential and sensitive information such as
financial, health, and governmental data.
II. PRIVACY CHALLENGES IN CLOUD
ENVIRONMENTS
Cloud computing is a modern technique of
computing in which resources are shared on the
Internet rather than on local servers. In other words,
it is storing and retrieving data using special
programs on the Internet instead of local computer
hard drives. The term cloud computing refers to
Internet-based computing in which different servers,
storage, and applications are used to deliver data and
reports anywhere anytime without having their own
system.
This section presents a summary of the main cloud
computing issues regarding security and privacy.
A. Loss of control
Loss of control is one of the main problems facing
cloud-computing. Cloud users fear losing control of
their data once they upload data to the cloud.
Universally, cloud systems are available to the
public. Also, the cloud provider owns the software,
hardware and the networks [5] that host the user
data. Every cloud user relies on the conventional
operations and technical standards without
considering the content of the information stored.
This makes cloud users worry about their data
getting lost or even being breached considering
cloud services operate on a multi-tenancy basis. [5].
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B. Lack of Transparency
Cloud computing suffers from a lack of transparency
in different ways reducing the credibility of
information stored. Cloud providers are unlikely to
share information concerning the methodologies,
processes, controls, and operations affecting the
cloud environment [6]. The willingness to share and
disclose secured information such as trade secrets is
a big issue facing this technology. There are laid
security principles which single out the types of
information that should be disclosed as well as those
that remain restricted [6]. Accessibility of data that
is has been archived is a major security problem that
takes longer than expected. A majority of times the
cloud user is not aware that accessing archived data
is a complex process signifying a lack of
transparency. The cloud provider is forced to engage
in negotiations with the user in order to find
common ground concerning the security of data
being stored. The levels of engagement are usually
elongated by mistrust between the two parties [6].
C. Multi-tenancy
Multi-tenancy architecture is an arrangement where
a single instance of a cloud service or application is
used for serving multiple consumers. Each of these
consumers is known as a tenant [6]. The tenants may
have permissions to modify the GUI and parts of
business rules for the applications, but cannot
customize or modify the core parts and code of the
application. Multi-tenancy is implemented by using
virtualization and remote access technologies [6].
Usually, the SaaS or Software-as-a-Service model is
used for delivering multi-tenancy architecture based
cloud services.
D. Virtualization
Refers to allowing large mainframes to be shared
amongst different applications within an
environment. Cloud computing has employed
virtualization at all levels to enhance security, reduce
costs as well as increase availability and reliability
[7]. Attacks on hypervisors are a reality since they
contain vulnerabilities making them prone to
exploitation by hackers. It is possible for Virtual
machine (VM) hijacking to happen which translates
to tricking the hypervisor to overwrite its memory
resulting to total exploitation. VM hopping is an
attack that allows for compromising of the VMs
projections and separations giving way for accessing
the hypervisors, other VMs, and the main computer.
VM Escape is another problem where an attacker
interacts with the hypervisor directly, after running
some codes that assist in breaking into the operating
system [7]. VM mobility takes place when an
attacker moves a VM between hosts physically.
E. Management
The management of cloud platform and a multi-
tenant architecture depends on various factors. The
basic factors are the type of cloud deployment model
and the SLA. If the deployment model is the public
cloud, then the service vendor will be responsible for
the management of the major parts of the application
[5].
The consumers may have limited capability to make
modifications. On the other hand, if the cloud
deployment model is private cloud, then the
enterprise can hire internal staff for the management
of the application
III. SOLUTIONS OF PRIVACY IN CLOUD
ENVIRONMENTS
A. Encryption Solution
Organizations using cloud computing and cloud data
systems need to protect their data more than the
organizations’ infrastructure [8]. Cloud data
encryption reduces the vulnerability of cloud data by
using encryption algorithms which match the degree
of sensitivity of cloud-stored data. Cloud data
encryption prevents unauthorized users from
accessing certain information from the cloud. Third-
party users can access classified information from
reliable sources [10]. Third party users are privileged
to enjoy interfaces that provide real-time delivery of
secured data [3].
B. Access Control Solution
Access control systems are a security solution to
user authentication in cloud computing [10]. For the
service provider, access control systems help in
providing data that has been verified to be of a given
clearance level [9]. Access control has enabled the
prevention of data theft. Only authorized persons
have the ability to transfer and provide data. This
helps companies and organizations to ensure that
qualified and authorized people have access to
classified data [9].
C. Third Party Audit
Third party audit (TPA) has the capability of
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maintaining and ensuring the integrity of data [11].
TPA is capable of monitoring data and information
stored in a cloud where users have to give a
signature before changing or adding any new
information [9]. TPA utilizes encryption systems
that are supported by hardware that is effective in
ensuring the integrity of data [11].
IV. SECURITY, PRIVACY AND TRUST
SOLUTIONS IN CLOUD ENVIRONMENTS
One of the main solutions for security, privacy and
trust concerns is the proper management of cloud
environments. In this section, we survey the
management of security, privacy and trust issues in
cloud environments. We also compare and contrast
these three issues in term of the following criteria:
Encryption, Access Control, Third Party Audit, and
Cloud Administration. We summarized the results of
our literature survey in Table 1.
Examples of encryption algorithms that address the
issue of security in cloud environments include
Rivest-Shamir- Adleman (RSA) [12] and Advanced
Encryption Standard (AES) [14]. The RSA
algorithm is an asymmetric cryptography algorithm
that uses public and private keys that are
mathematically linked. AES is a symmetric
encryption algorithm that is fast to encrypt and
decrypt messages. A cloud environment would use
the RSA to exchange keys securely and use AES to
encrypt and decrypt the actual message. Both
methods are used in the cloud even though they
serve different purposes.
Encryption is also used to address the privacy issue
in the cloud. For example, the Data Encryption
Standard (DES) [15], and PCM [16] address the
privacy issue in cloud environments. The DES
assumes that both the sender and receiver know the
private keys. Thus, makes it less secure than AES.
TABLE I: Security and Privacy Challenges vs.
Solutions [9]
Encryption is also used in literature to address the
problem of Trust in Cloud Environments. Diffie
Hellman (DH) [17] represents security methods to
secure malicious attacks on the cloud. This is
completely avoided by DH key exchange algorithm.
Beside this, DH protocol is useful when the number
of users on the cloud is very large and key
management is very difficult.
Access Control gives users limited authorization to
connection network, data, and system files. Also, it
manages who or what can use resources in the
cloud- computing environment. Access control could
be used to solve the security issues in cloud
computing by more than two schemes such as Role-
based access control (RBAC) [18], and
Discretionary Access Control (DAC) [19]. These
methods give the ability to the individual user to
access cloud computing and perform a specific task
like create, view or modify a file. Mandatory Access
Control (MAC) [20] is used in multi-level security
systems where the administrator of the system
decides the access permissions. In Ciphertext-Policy
Attribute-Based Encryption (CP-ABE) [21] a user’s
private key is associated with a set of attributes and a
certain cipher text specifies an access control policy
for defined metrics within the managed system.
Third party audit uses multiple methods to address
all the management problem in cloud computing. In
the security area, we can use a Holomorphic linear
authenticator (HLA) [21]. By using HLA the TPA
will not know any information about data stored in
cloud during the auditing process.
Hashed Message Authentication Codes (HMAC)
[18] is a third party audit method to solve privacy
issues in cloud computing using a private key. Users
have to make a unique HMAC in their request.
Table I summarizes the different privacy problems
and their available solutions in the cloud. As we
notice from the table, the Encryption solution can be
applied to solve the problem of Loss of Control,
Multi-tenancy, Visualization, and Management
privacy problems. Similarly, we notice that the
Access control solution could be used to address the
issue of Loss of Control, Multi-tenancy,
Virtualization, and Management problems. Also, the
Third Party Audit solution could be used to address
the problem of Loss of Control, Lack of
Transparency, Multi-tenancy, Virtualization, and
Management problems. The Isolation solution could
be used to handle the Multi-tenancy and
Virtualization cloud privacy issues.
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V. USER PRIVACY FRAMEWORK
We provide a framework model for illustrating
privacy in a cloud environment as showing in Figure
1
Figure1 user privacy framework
Cloud client: There are numerous sorts of clients.
These clients incorporate people, Companies
(Organizations), Non-Governmental Organizations
(NGO), Governments, and Security Third Party
Evaluators. The Cloud Clients interact with the
cloud environment through the Protection
Administration Interface (PMI).
Privacy Management Interface (PMI): Usually
done by means of scrambled secured communication
that translates the submitted task for the quality of
service. The PMI is additionally utilized to transmit
the status of the benefit demands to the cloud buyers
and the third-party protection inspectors. The PMI
takes the task and passes it to the Protection Finder
(PD) to identify any protection infringement and
guarantee that protection limitations and rules are
met concurring to the Benefit Level Understandings
between the cloud buyer and the cloud supplier.
Protection Privacy Finder: The Protection Finder
(PF) screens the submitted client demands to check
for any protection concerns and to form beyond any
doubt that all approaches and client necessities are
not abused. We utilize our security show to speak to
the sort of protection rules. The PD communicates
with the Cloud environment to check for security
concerns.
Protection Screen Monitor: The Protection Screen
(PS) guarantees that all privacy-related rules are
continuously met. It does that by checking all the
communications between the Virtual Machines
(VMs) and the genuine Administration Cloud Assets
(MCRs). Sense repository
Access control policy: log file Access control is
another approach to solve the privacy issue. With
this method, privacy is addressed by defining
authorization access rules and by representing
private data in cloud computing environments.
Third-party auditing is another significant method to
handle attacks based on static and dynamic analysis
tools.
In the management method, an organization should
identify privacy policy and procedures to recognize
the migration process risk. In this approach
management methods deal with secure testing, tree
analysis including static analysis approaches to
preserve privacy policy over global
computing.
Encryption Method: Encryption is a method that is
used to handle privacy by analysing the
homographic encryption code to handle the security
holes that can be used by an attacker to destroy the
system and compromise user’s privacy. Cloud
computing providers deliver applications via the
internet, which is accessed from web browsers,
desktop, and mobile apps, while the business
software and data are stored on servers at a remote
location. In some cases, legacy applications (line of
business applications that until now have been
prevalent in thin client Windows computing) are
delivered via a screen-sharing technology, while the
computing resources are consolidated at a remote
data center location; in other cases, entire business
applications have been coded using web-based
technologies
Virtual Knowledge-Based offer cloud
resource:
It passes cloud benefit demands and gets the reaction
to these demands through the PMI layer by means of
a secured, scrambled, hashed, and carefully marked
communication. The information demands are put
away in an Information Base (KB) in a scrambled
area within the Cloud Environment. Asset revelation
may be depicted fundamentally as the errand in
which the supplier ought to discover suitable assets
in arrange to comply with approaching buyers
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demands considering that one of the key highlights
of cloud computing is the capability of procuring
and discharging assets on request asset observing
ought to be continuous.
VI. CASE STUDIES
Over recent years, different sectors have continued
to adopt modern ways brought about by information
technology. Cloud computing is one of the magical
ways that has continued to gain much traction
especially in the delivery of services over the
Internet and storage of data. Both the individuals and
organizations are benefiting from the cloud through
a cost-effective utility that is leading to business
empowerment. Nonetheless, with all the benefits
arising from cloud computing, it has experienced its
fair share of challenges particularly with respect to
privacy, trust, and confidentiality.
A. Case Study 1: Providing Security for Health Care
Providers
Modern information technology has been overly
embraced by the healthcare sector leading to the
revamping of the way services are delivered. In the
developing world, particularly in Africa, they have
not been left out in utilizing cloud technology in
relation to their healthcare system. They have
realized that technology enhances the reliability and
availability of improved health care services to
patients at a friendly cost. The cloud-based medical
information system will introduce a drastic reduction
in healthcare service, resource utilization, as well as
maintainability and adoption of new technologies.
The healthcare industry in a majority of the
developing countries has not succeeded to fully tap
the modern information technology with regards to
improving delivery of healthcare services. Accesses
to the longitudinal records of the patients often prove
to be a tenacious and cumbersome task. Apparently,
a lack of proper access to documents has been a
costly affair to the institution mainly due to wastage
and duplication. In this regard, they have decided to
embrace technology in the sector and adopt services
of cloud infrastructure. They have proposed that
healthcare providers be sharing data across a newly
proposed engineering network solution system for
data sharing. Fundamentally, this will guarantee the
privacy of the patient information in an electronic
health record [15]. Unluckily, the system due to
weaker security system has been leaking sensitive
information about the patients, thereby violating
their right to confidentiality.
Algorithm encryption is a cloud security measure
that if implemented correctly guarantees privacy to
the information stored in the cloud infrastructure.
With the advent of cloud computing, it is critical that
the health sector realizes some tight measures to
secure data. The health institution ought not to rely
on encryption only as secrecy remains to be
ultimate. In this case, homophobic encryption would
be the best advisable way to ensure data
confidentiality. It is possible to conduct a direct
computation operation targeting cipher-texts by way
of analyzing the functioning of plaintexts [19].
For a sample dataset, we consider patient records.
We use The Ontology Web Language (OWL) to
store these records in the cloud. The following OWL
code represents a patient’s records [20].
Patient Records Example [20]
This OWL code is machine readable and since
patient records are private and confidential, it can be
encrypted using an encryption key and securely
stored in the cloud.
B. Case Study 2: Establishing Trust via Third Party
Auditing
Trust issues within the cloud infrastructure have
proved to be a recurring challenge. Cloud service
users (CSUs) look for the cloud service providers
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(CSPs) that are trustworthy with information stored.
It is known that security information is often highly
guarded to avoid cases of jeopardizing the stability
of a state or even an organization. A Securicor
security is a company that deals with providing
security services to homes, institutions, and even
government buildings. The company conducts
impromptu meetings whenever they need to discuss
the security status of organizations under their
banner. Due to the humongous number of files, the
firm has decided to contract a CSP for purposes of
storing their information and enhancing service
delivery.
It is critical for CSPs to implement robust
compliance and verification processes in an effort to
ensure they conform to the audit and support
functions. In this case, the CSP ought to ensure it
conducts a coordinated combination of defined as
well as consistent internal policy compliance. The
company contracted to audit the info should be
independent for purposes of transparency. Upon
contracting, the selected auditor should start by first
performing initial data gathering to comprehend the
positioning of the cloud [18]. Besides, the auditor
will have identified the information processed in the
cloud over and above the cloud service model in use.
Once the auditor has identified all the above, the
next step would be to establish audit activities and
plans including reviews addressing the problems
related to the existent policies [19]. In the end, the
CSPs should obtain a third party assurance report,
which will act as a pointer to the assessors and
auditors in the future.
We consider audit records from CSP file records and
give a machine readable OWL code which can be
encrypted to avoid cyberattack on government data
which is very sensitive for as far as stability of a
nation is concerned [21].
Audit Records Example [21]
C. Case Study 3: Detection of Fraud in Banking
Systems
Cybercrimes have been rife despite the continued
embracement of cloud technology by institutions
such as banks. Fraud cases have increased
considering that buying cloud services is cheap, it
can be done under an anonymous tag, and
geographical location is not a hindrance. The recent
Operation High Roller by MacAfee is a classic
illustration of the seriousness of the fraud problem.
An international criminal gang was involved in the
crime. It targeted commercial accounts of wealthy
people banking with European banks. It is estimated
that money lost through the fraud amounted to
approximately two billion dollars. Markedly, the
cloud infrastructure was at the center stage of the
scam. It was supplemented by the gang’s knowledge
of the transaction systems within the bank together
with servers, which facilitated the theft automation.
Remarkably, the fraud was initiated by a disguised
email that likened that of the recipient’s bank. Upon
clicking the message link, it would automatically
install malware that would make it possible for the
fraudsters to transfer funds. Due to the huge loss,
there was a need to conduct an upgrade of the third
party auditor.
Fig. 3: Case 3 (Detection of Fraud in Banking
Systems)
Improving on the third party auditing would be the
best solution to curb the occurrence of such a fraud
in the future. CSUs commercial banks themselves
ought to contract CSPs after determining their audit
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requirements as well their capacity to perform third-
party audits regularly [13]. Selection of CSP should
be pegged on their transparency ratings in terms of
policies and security engrained in the cloud
infrastructure. On the other hand, the CSPs top
commercial banks ought to provide a comprehensive
data processing agreement in an effort to address the
security and privacy problem affecting their client’s
data [16]. Moreover, they should provide built-in
controls and capabilities to aid the CSUs to meet
both internal compliance requirements and industry
regulations. In addition, a commercial bank should
engage large global technology firms with third-
party certification and be including ISO 27001.
Essentially, improving on CSPs third-party auditing
conformation standards will go a long way in
eliminating the substandard ones.
Bank details are at a high risk of cyberattack due to
the money component. Many fraud cases have been
reported simply because hackers were able to access
the details of a bank customer online. To avoid such
cases especially with cloud computing, data
encryption is key for bank records stored in the
cloud. The following is a sample dataset for bank
details of a client in Barclays bank in the UK [22]. It
is presented in the form of an OWL code which is
machine readable and easily encrypted using an
encryption key to avoid unauthorized access.
Account Details Example [22]
VII. CONCLUSION AND FUTURE WORK
Cloud environments lack the proper support for the
privacy of cloud consumers’ data. This study was
conducted in an attempt to address the privacy
concerns in cloud environments. We surveyed
existing challenges and obstacles that concern the
privacy, security, and trust in the cloud. We also
surveyed different solutions that are available in the
literature and compared them. Each solution has its
strengths and weaknesses. We proposed a
framework for preserved user privacy over the
cloud. Our experiment shows that a hybrid solution
that includes more than one solution would provide a
more reliable and secure environment.
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