Int. J. Communications, Network and System Sciences, 2011, 4, 152-163
doi:10.4236/ijcns.2011.43019 Published Online March 2011 (
Copyright © 2011 SciRes. IJCNS
A User Identity Management Protocol for Cloud
Computing Paradigm
Safiriyu Eludiora1, Olatunde Abiona2, Ayodeji Oluwatope1, Adeniran Oluwaranti1,
Clement Onime3, Lawrence Kehinde4
1Department of Computer Science and Engineering, Obafemi Awolowo University, Ile-Ife, Nigeria
2Department of Computer Information Systems, Indiana University Northwest, Garry, USA
3Information and Communication Technology Section, Abdus Salam International Centre for Theoretical Physics,
Trieste, Italy
4Department of Eng ineering Technologies, Texas Southern Un iversity , Housto n , USA
E-mail: {sieludiora , aoluwato, arant i},, on,
Received January 3, 2011; revised February 9, 2011; accepted February 11, 2011
Cloud computing paradigm is a service oriented system that delivers services to the customer at low cost.
Cloud computing needs to address three main security issues: confidentiality, integrity and availability. In
this paper, we propose user identity management protocol for cloud computing customers and cloud service
providers. This protocol will authenticate and authorize customers/providers in other to achieve global secu-
rity networks. The protocol will be developed to achieve the set global security objectives in cloud comput-
ing environments. Confidentiality, integrity and availability are the key challenges of web services’ or utility
providers. A layered protocol design is proposed for cloud computing systems, the physical, networks and
application layer. However, each layer will integrate existing security features such as firewalls, NIDS, NIPS,
Anti-DDOS and others to prevent security threats and attacks. System vulnerability is critical to the cloud
computing facilities; the proposed protocol will address this as part of measures to secure data at all levels.
The protocol will protect customers/cloud service providers’ infrastructure by preventing unauthorized users
to gain access to the service/facility.
Keywords: Cloud Computing, Confidentiality, Integrity, Availability, Identity Management, Authentication
1. Introduction
In cloud computing, resources are provided as a service
over the Internet to customers who use them as when
needed basis. Computing services are available through
data centers and accessible anywhere, so that the cloud is
a single point of access for tools that address the entire
customer’s computing needs.
The cloud—characterized by large scale complexes
for data storage and processing, delivery of software as
an online service and leveraged connection of wireless
devices to services and applications offered online—
promises systemic and economic changes for business.
As customers generally do not own the computing infra-
structure but access or rent cloud computing services,
cloud computing minimizes capital expenditure and
lowers barriers to entry. By uncoupling computing tools
from physical location, cloud computing enables users to
access data and systems regardless of geography or
available media [1].
Cloud management—To conduct business within a
cloud (recognizing what is available today), it is impor-
tant for cloud consumers and providers to align on
graduated SLAs and corresponding pricing models.
Maturing cloud capabilities into more advanced offer-
ings, such as virtual supply chains, requires support for
fully abstracted, policy-driven interactions across clouds.
It will become a major challenge for the cloud providers
to adequately model, expose and extend policies in order
to provide integrated services across distributed and het-
erogeneous business processes and infrastructure. The
data associated with these business processes and infra-
structure will need to be managed appropriately to ad-
dress and mitigate various risks from a security, privacy,
and regulatory compliance perspective. This is particu-
larly important as intellectual property, customer, em-
ployee, and business partner data flows across clouds and
along virtual supply chains [2].
“Cloud computing is the use of networked infrastruc-
ture software and capacity to provide resources to users
in an on-demand environment. Sometimes known as
utility computing, clouds provide a set of typically virtu-
alized computers which can provide users with the abil-
ity to start and stop servers or use compute cycles only
when needed, often paying only upon usage” [3]. Figure
1 shows a typical used case scenarios architecture. There
are service provider, service consumer, and service de-
veloper. Within the service provider there is security and
management. Our focus is security with emphasis on
identity management. In this paper, a scenario of an or-
ganization is considered. The identity provided for that
employee must be used for every purpose that warrants
the use of ID. Therefore, most of the existing IDM can-
not be used for all situations. The federated IDM sounds
appropriate. The federated IDM need to be enhanced
high level of security.
1.1. Benefits of Cloud Computing
To deliver a future state architecture that captures the
promise of Cloud Computing, architects need to under-
stand the primary benefits of Cloud computing:
• Decoupling and separation of the business service
from the infrastructure needed to run it (virtualization).
• Flexibility to choose multiple vendors that provide
reliable and scalable business services, development en-
vironments, and infrastructure that can be leveraged out
of the box and billed on a metered basis—with no long
term contracts.
• Elastic nature of the infrastructure to rapidly allocate
and de-allocate massively scalable resources to business
services on a demand basis.
• Cost allocation flexibility for customers wanting to
move Capital exchange into Operational exchange.
• Reduced costs due to operational efficiencies, and
more rapid deployment of new business services [4].
Cloud computing infrastructures can allow enterprises
to achieve more efficient use of their IT hardware and
software investments. They do this by breaking down the
physical barriers inherent in isolated systems, and auto-
mating the management of the group of systems as a
single entity.
Cloud computing is an example of an ultimately virtu-
alized system, and a natural evolution for data centers
that employ automated systems management, workload
balancing, and virtualization technologies.
A cloud infrastructure can be a cost efficient model for
delivering information services, reducing IT manage-
ment complexity, promoting innovation, and increasing
responsiveness through real-time workload balancing.
The Cloud makes it possible to launch Web 2.0 appli-
cations quickly and to scale up applications as much as
when needed. The platform supports traditional Java™
and Linux, Apache, MySQL, PHP (LAMP) stack-based
applications as well as new architectures such as Map-
Reduce and the Google File System, which provide a
means to scale applications across thousands of servers
Large amounts of computer resource, in the form of
Xen virtual machines, can be provisioned and made
available for new applications within minutes instead of
days or weeks. Developers can gain access to these re-
sources through a portal and put them to use immediately.
Several products are available that provide virtual ma-
chine capabilities, including proprietary ones such as
VMware, and open source alternatives, such as XEN [5].
Source: Cloud Computing Use Case Discussion Group
Figure 1. Cloud computing architecture.
Copyright © 2011 SciRes. IJCNS
Copyright © 2011 SciRes. IJCNS
1.2. Delivery Models and Security Issues of
Cloud Computing
The NIST [6] definition of cloud computing defines
three delivery models:
1.2.1. Software as a Service (SaaS)
The consumer uses an application, but does not control
the operating system, hardware or network infrastructure
on which it’s running.
The SaaS model dictates that the provider manages the
entire suite of applications delivered to end-users. There-
fore SaaS providers are mainly responsible for securing
these applications. Customers are normally responsible
for operational security processes (user and access man-
agement). However the following questions, along with
other sections within this document, should assist in as-
sessing their offerings:
• What administration controls are provided and can
these be used to assign read and write privileges to other
• Is the SaaS access control fine grained and can it be
customized to ones organizations policy?
1.2.2. Platform as a Service (PaaS)
The consumer uses a hosting environment for their ap-
plications. The consumer controls the applications that
run in the environment (and possibly has some control
over the hosting environment), but does not control the
operating system, hardware or network infrastructure on
which they are running. The platform is typically an ap-
plication framework. Generally speaking, PaaS service
providers are responsible for the security of the platform
software stack, and the recommendations throughout this
document are a good foundation for ensuring a PaaS
provider has considered security principles when de-
signing and managing their PaaS platform. It is often
difficult to obtain detailed information from PaaS pro-
viders on exactly how they secure their platforms –
however the following questions, along with other sec-
tions within this document, should be of assistance in
assessing their offerings.
• Request information on how multi-tenanted applica-
tions are isolated from each other—a high level descrip-
tion of containment and isolation measures is required.
• What assurance can the PaaS provider give that ac-
cess to your data is restricted to your enterprise users and
to the applications you own?
• The platform architecture should be classic “sand-
box”—does the provider ensure that the PaaS platform
sandbox is monitored for new bugs and vulnerabilities?
• PaaS providers should be able to offer a set of secu-
rity features (re-useable amongst their clients) – do these
include user authentication, single sign on, authorisation
(privilege management), and SSL/TLS (made available
via an API)?
1.2.3. Infrastructure as a Service (IaaS)
The consumer uses “fundamental computing resources”
such as processing power, storage, networking compo-
nents or middleware. The consumer can control the op-
erating system, storage, deployed applications and possi-
bly networking components such as firewalls and load
balancers, but not the cloud infrastructure beneath them.
As with personnel security, many of the potential issues
arise because the IT infrastructure is under the control of
a third party – like traditional outsourcing, the effect of a
physical security breach can have an impact on multiple
customers (organizations).
• What assurance can you provide to the customer re-
garding the physical security of the location? Please pro-
vide examples, and any standards that are adhered to, eg,.
Section 9 of ISO 27001/2.
• Who, other than authorized IT personnel, has unes-
corted (physical) access to IT infrastructure?
For example, cleaners, managers, “physical security”
staff, contractors, consultants, vendors, etc.
• How often are access rights reviewed?
• How quickly can access rights be revoked?
• Do one assess security risks and evaluate perimeters
on a regular basis?
• How frequently?
Do you carry out regular risk assessments which
include things such as neighboring buildings?
Do you control or monitor personnel (including
third parties) who access secure areas?
What policies or procedures do you have for load-
ing, unloading and installing equipment?
Are deliveries inspected for risks before installa-
Is there an up-to-date physical inventory of items in
the data centre?
Do network cables run through public access areas?
• Do you use armored cabling or conduits?
Do you regularly survey premises to look for unau-
thorized equipment?
Is there any off-site equipment?
• How is this protected?
Do your personnel use portable equipment (eg,. lap-
tops, smart phones) which can give access to the data
• How are these protected?
What measures are in place to control access cards?
What processes or procedures are in place to de-
stroy old media or systems when required to do so?
• Data overwritten?
• Physical destruction?
What authorization processes are in place for the
movement of equipment from one site to another?
• How do you identify staff (or contractors) who are
authorized to do this?
How often are equipment audits carried out to
monitor for unauthorized equipment removal?
How often are checks made to ensure that the envi-
ronment complies with the appropriate legal and regula-
tory requirements [7,8]. In the next subsection we dis-
cuss different deployment models.
1.3. Deployment Models of Cloud Computing
The NIST definition defines four deployment models:
1.3.1. Public Cloud
In simple terms, public cloud services are characterized
as being available to clients from a third party service
provider via the Internet. The term “public” does not
always mean free, even though it can be free or fairly
inexpensive to use. A public cloud does not mean that a
user’s data is publically visible; public cloud vendors
typically provide an access control mechanism for their
users. Public clouds provide an elastic, cost effective
means to deploy solutions.
1.3.2. Private Cloud
A private cloud offers many of the benefits of a public
cloud computing environment, such as being elastic and
service based.
The difference between a private cloud and a public
cloud is that in a private cloud-based service, data and
processes are managed within the organization without
the restrictions of network bandwidth, security exposures
and legal requirements that using public cloud services
might entail. In addition, private cloud services offer the
provider and the user greater control of the cloud infra-
structure, improving security and resiliency because user
access and the networks used are restricted and desig-
1.3.3. Community Cloud
A community cloud is controlled and used by a group of
organizations that have shared interests, such as specific
security requirements or a common mission. The mem-
bers of the community share access to the data and ap-
plications in the cloud.
1.3.4. Hybrid Cloud
A hybrid cloud is a combination of a public and private
cloud that interoperates. In this model users typically
outsource non-business-critical information and process-
ing to the public cloud, while keeping business-critical
services and data in their control. [7]
1.4. Essential Characteristics of Cloud
The NIST definition describes five essential characteris-
tics of cloud computing.
1.4.1. Rapid Elasticity
Elasticity is defined as the ability to scale resources both
up and down as needed. To the consumer, the cloud ap-
pears to be infinite, and the consumer can purchase as
much or as little computing power as they need. This is
one of the essential characteristics of cloud computing in
the NIST definition.
1.4.2. Measured Service
It is a measured service, aspects of the cloud service are
controlled and monitored by the cloud provider. This is
crucial for billing, access control, resource optimization,
capacity planning and other tasks.
1.4.3. On-Demand Self-Service
The on-demand and self-service aspects of cloud com-
puting mean that a consumer can use cloud services as
needed without any human interaction with the cloud
1.4.4. Ubiquitous Network Access
Ubiquitous network access means that the cloud pro-
vider’s capabilities are available over the network and
can be accessed through standard mechanisms by both
thick and thin clients.
1.4.5. Resource Pooling
Resource pooling allows a cloud provider to serve its
consumers via a multi-tenant model. Physical and virtual
resources are assigned and reassigned according to con-
sumer demand. There is a sense of location independence
in that the customer generally has no control or knowl-
edge over the exact location of the provided resources
but may be able to specify location at a higher level of
abstraction (e.g., country, state, or datacenter) [7]. In
essence security is the key challenge in exploring the
benefits of cloud computing.
In this paper, we proposed user-IDM protocol (U-IDM).
This work review available literature and general issues
on cloud computing environments. In Section 1 we dis-
cuss a general introduction; the section introduces the
key areas of cloud computing, and deployment models.
In Section 2 we discuss scientific overview of security
and cloud computing Identity management. Section 3
describes the theoretical frame work and our research
philosophy. Section 4 discusses the proposed algorithms,
in Section 5 we describe the simulations. Section 6 out-
lined the results and the paper was concluded in Section 7.
Copyright © 2011 SciRes. IJCNS
2. Overview
In this section, we discussed security and IDM issues in
cloud computing environment and steps to be taken by
cloud services’ providers and customers alike.
2.1. Security
Security is the most important part of the total solution
and requires end-to-end security practices. From an iden-
tity and access perspective, the enterprise can provide an
identity authentication service for its employees regard-
less of where the service resides, either internally or in
the cloud computing environment. The company owns
and manages the employee’s identity repository and does
not share identities with any other entity. The company
provides a central point in managing an employee’s
identity, including password preset/reset/changes.
The company enhances identity and security protec-
tion by protecting an employee’s confidential and cre-
dential information, because the identity federation ap-
proach allows the enterprise to manage its employee’s
access control policy—determining where single sign on
(SSO) occurs, asserting trust appropriately, and sharing
acceptable attributes between the identity provider and
the service provider.
From an end user’s perspective, remote access can re-
inforce security by using advanced authentication
mechanisms (such as strong authentication or multifactor
authentication) to prevent identity theft over the Internet,
or to leverage the Host Checker to verify allowed hard-
ware, thereby ensuring a safe environment [9]. This may
be referred to as information security.
2.2. Information Security
Security is a property of a well-designed system accord-
ing FISMA [10]. The term information security means
protecting information and information systems from
unauthorized access, use, disclosure, disruption, modifi-
cation, or destruction [11] to provide confidence, integ-
rity and availability for the users.
Confidentiality: Preserving authorized restrictions on
access and disclosure, including means for protecting
personal privacy and proprietary information.
Integrity: Guarding against improper information mo-
dification or destruction; includes ensuring information
non-repudiation and authenticity.
Availability: Ensuring timely and reliable access to
and use of information to the users.
Security is not a feature; it is a property of a system. It
results from thorough analysis of security requirements,
sound architecture and design, and secure coding prac-
tices [12]. Personnel security also enhance these features,
organizations need to comply with rules and regulations
laid down by the cloud service providers for the cloud
2.3. Personnel Security
The majority of questions relating to personnel will be
similar to those one would have asked his own IT per-
sonnel or other personnel who are dealing with IT. As
with most assessments, there is a balance between the
risks and the cost.
• What policies and procedures do you have in place
when hiring your IT administrators or others with system
access? These should include:
pre-employment checks (identity, nationality or status,
employment history and references, criminal convictions,
and vetting (for senior personnel in high privilege roles)).
• Are there different policies depending on where the
data is stored or applications are run? For example, hir-
ing policies in one region may be different from those in
Practices need to be consistent across regions.
It may be that sensitive data is stored in one par-
ticular region with appropriate personnel.
• What security education program do you run for all
• Is there a process of continuous evaluation?
How often does this occur?
Further interviews
Security access and privilege reviews
Policy and procedure reviews.
2.4. Security Issues of Cloud Computing
Despite the beauty of Cloud computing application ser-
vice, as mentioned earlier, Cloud service subscribers,
particularly for larger enterprises with corporate infor-
mation security policies need to be enforced from time to
time, they may want to consider getting a security as-
sessment from a neutral third party before committing to
a Cloud vendor.
Gartner [13] noted that Cloud computing is fraught
with security risks and seven specific security issues are
brought to the attention of potential Cloud service sub-
scribers that they should raise them with their providers
before actually selecting them:
Privileged user access—ask the providers to supply
specific information on the hiring and oversight of privi-
leged administrators, and the control over their access,
because outsourced services usually bypass the “physical,
logical and personnel security controls” which exert over
in-house programs.
Regulatory compliance—the providers who refuse to
undergo this scrutiny are “signaling that subscribers can
Copyright © 2011 SciRes. IJCNS
only use them for the most trivial functions”, as sub-
scribers are ultimately responsible for the security and
integrity of their own data even when it is held by a ser-
vice provider.
Data locat ion—ask the providers if they will “commit
to storing and processing data in specific jurisdictions
and whether they will make a contractual commitment to
obey local privacy requirements on behalf of the sub-
Data segregation—subscribers’ data should be segre-
gated with data from other customers as the Cloud is
typically a shared environment. The service providers
should provide data encryption as options and evidence
on the corresponding encryption schemes were designed
and properly tested by experienced specialists, as “en-
cryption accidents can make data totally unusable”.
Recovery—ask the providers if they have implemented
and tested any disaster recovery procedures (DRP) which
provides them with “the ability to do a complete restora-
tion” and most importantly, “how long it will take” to
execute the DRP [14]. Security attributes of cloud com-
puting are discussed, so that the entire system is reliable
and accessible to the users.
2.5. Network Security Attributes of Cloud
These basic security issues are: authentication, authori-
zation, auditing, confidentiality, integrity, availability and
Authentication: is a process by which one entity veri-
fies the identity of another entity. This can be a person or
program. The authentication process can be done in three
ways; something that user knows such as password or
login name, something user has such as personal identi-
fication number (PIN) and something user is such as
finger print. There is could be a message authentication
system that determines the source of message. Another
authentication process can be machine-to-machine, which
can be client, server and/or mutual authentications. Cli-
ent authentication involves the server verifying the cli-
ent’s identity, server authentication involves the client
verifying the server’s identity and mutual authentication
involves the client and server verifying each other’s
identity. In the context of UCS, a web server can be au-
thenticated, so that user can deal with a real website, and
not an imitating (disguising) web server. Transport layer
socket (TLS) can be used for this process.
Authorization: is the process that ensures that a person
has the right to access certain resources. Users can not be
allowed to access any resources without knowing the
attributes of such users. Users can have access rights to
resources; but the authority to do something is not within
their reach. For example, a user can use ATM card to
withdraw money from the ATM machine. Having been
authenticated, he cannot withdraw beyond a recom-
mended maximum irrespective of any amount he has in
his bank account. Cloud computing uses these access
control and authorization to regulate resources usage and
minimize fraudulent practices [15].
Auditing: is a process of collecting information about
user attempting access to a particular resource, or per-
forms actions. The log in system must be able to record
all actions performed on that resource. In case there is
any problem, the log file can be checked to trace such a
user out.
Confidentiality (privacy): is an act that keeps private
or sensitive information from being disclosed to unau-
thorized individuals, entities or processes. In cloud com-
puting environment, it is important to maintain transac-
tions’ secrecy, because e-payment instruments like visa
are involved.
Integrity: is the ability to protect data from being al-
tered or destroyed by unauthorized persons or processes
during the course of transmission. This is important in
cloud computing environment, because the mobile de-
vices use air medium and for this reason, data must be
well protected.
Availability: is the unhindered accessibility of a ser-
vice. An online service is available if a user or program
can gain access to the pages, data, or services provided
by the site when they are needed. This is critical to UCS.
Unavailability of a web site may hinder the on-going
transactions and it may lead to loss of money and cus-
tomers. Technologies such as load balancing hardware
and software are aimed at ensuring availability [16].
Non-repudiation: is the ability to limit parties from
refuting that a legitimate transaction took place. Since
cloud computing transactions involve money, it is im-
portant that the customer commits himself by endorsing
his/her signature [16,17]. It is obvious that these attrib-
utes may be difficult to achieve, we therefore proposed a
“User Identity Management Protocol (U-IDMP). In this
case the emphasis is on user attributes provided by the
enterprises for cloud service providers to verify such a
2.6. User Identity Management
Whether an application runs on-premises or in the cloud, it
typically needs to know something about its users. Toward
this end, the application commonly demands that each
user provides a digital identity, a set of bytes that describes
that user. Based on what these bytes contain and how
they’re verified, the application can determine things such
as who this user is and what they’re allowed to do.
Copyright © 2011 SciRes. IJCNS
Many on-premises applications today rely on an on-
premises infrastructure service, such as Active Directory,
to provide this identity information. When a user ac-
cesses a cloud application, however, or an on-premises
application accesses a cloud service, an on-premises
identity usually won’t work. And what about an applica-
tion built on a cloud foundation? Where does it get its
identity information?
An identity service in the cloud can address these is-
sues. Because it provides a digital identity that can be
used by people, by on-premises applications, and by
cloud applications, a cloud identity service can be ap-
plied in many different scenarios. In fact, one indication
of the importance of this kind of identity service is the
number of cloud identity services available today. Ac-
cessing Amazon cloud services such as EC2 or S3 re-
quires presenting an Amazon-defined identity, for in-
stance, while using Google AppEngine requires a Google
account. Microsoft provides Windows Live ID, which
can be used for Microsoft applications and others, while
BizTalk Services also offers its own identity service,
which can be federated with others. Developers don’t
have complete freedom—cloud platforms are frequently
tied to a particular identity provider—but the need for
identity as a cloud service is clears [1].
2.7. Identity and Access Management
The following controls apply to the cloud provider’s
identity and access management systems (those under
their control).
2.7.1. Authorization
• Do any accounts have system-wide privileges for the
entire cloud system and, if so, for what operations
• How are the accounts with the highest level of privi-
lege authenticated and managed?
• How are the most critical decisions (e.g., simultane-
ous de-provisioning of large resource blocks) authorized
(single or dual, and by which roles within the organiza-
• Are any high-privilege roles allocated to the same
person? Does this allocation break the segregation of
duties or least privilege rules?
• Do you use role-based access control (RBAC)? Is the
principle of least privilege followed?
• What changes, if any, are made to administrator
privileges and roles to allow for extraordinary access in
the event of an emergency?
• Is there an “administrator” role for the customer? For
example, does the customer administrator have a role in
adding new users (but without allowing him to change
the underlying storage!)?
2.7.2. Identity Provisioning
• What checks are made on the identity of user accounts
at registration? Are any standards followed? For example,
the e-Government Interoperability Framework?
• Are there different levels of identity checks based on
the resources required?
• What processes are in place for de-provisioning cre-
• Are credentials provisioned and de-provisioned si-
multaneously throughout the cloud system, or are there
any risks in de-provisioning them across multiple geo-
graphically distributed locations?
2.7.3. Management Personal Data
• What data storage and protection controls apply to the
user directory (e.g., AD, LDAP) and access to it?
• Is user directory data exportable in an interoperable
• Is need-to-know the basis for access to customer data
within the cloud provider?
2.7.4. Key Management
• For keys under the control of the cloud provider:
• Are security controls in place for reading and writing
those keys? For example, strong password policies, keys
stored in a separate system, hardware security modules
(HSM) for root certificate keys, smart card based authen-
tication, direct shielded access to storage, short key life-
time, etc.
• Are security controls in place for using those keys to
sign and encrypt data?
• Are procedures in place in the event of a key com-
promise? For example, key revocation lists.
• Is key revocation able to deal with simultaneity is-
sues for multiple sites?
• Are customer system images protected or encrypted?
2.7.5. Encryption
• Encryption can be used in multiple places—where is it
data in transit
data at rest
data in processor or memory?
Usernames and passwords?
• Is there a well-defined policy for what should be en-
crypted and what should not be encrypted?
• Who holds the access keys?
• How are the keys protected?
2.7.6. Authentication
• What forms of authentication are used for operations
requiring high assurance? This may include login to
management interfaces, key creation, access to multi-
Copyright © 2011 SciRes. IJCNS
ple-user accounts, firewall configuration, remote access, etc.
• Is two-factor authentication used to manage critical
components within the infrastructure, such as firewalls,
2.7.7. Credential Compromise or Theft
• Do you provide anomaly detection (the ability to spot
unusual and potentially malicious IP traffic and user or
support team behavior)? For example, analysis of failed
and successful logins, unusual time of day, and multiple
logins, etc.
• What provisions exist in the event of the theft of a
customer’s credentials (detection, revocation, evidence
for actions)?
2.8. Identity and Access Management Systems
Offered to the Cloud Customer
The following questions apply to the identity and access
management systems which are offered by the cloud
provider for use and control by the cloud customer.
2.8.1. Identity Management Frameworks
• Does the system allow for a federated IDM infrastruc-
ture which is interoperable both for high assurance (OTP
systems, where required) and low assurance (e.g. user-
name and password)?
• Is the cloud provider interoperable with third party
identity providers?
• Is there the ability to incorporate single sign-on?
2.8.2. Access Control
• Does the client credential system allow for the separa-
tion of roles and responsibilities and for multiple domains
(or a single key for multiple domains, roles and respon-
• How do you manage access to customer system im-
ages—and ensure that the authentication and crypto-
graphic keys are not contained within in them?
2.8.3. Authentication
• How does the cloud provider identify itself to the cus-
tomer (i.e., is there mutual authentication)?
when the customer sends API commands?
when the customer logs into the management inter-
• Do you support a federated mechanism for authenti-
End Users need to access certain resources in the
cloud and should be aware of access agreements such as
acceptable use or conflict of interest. In this model, end
user signatures may be used to confirm if someone is
committed to such policies. The client organization should
run mechanisms to detect vulnerable code or protocols at
entry points such as firewalls, servers, or mobile devices
and upload patches on the local systems as soon as they
are found. Thus, this approach ensures security on the
end users and on the cloud alike.
However, the cloud needs to be secure from any user
with malicious intent that may attempt to gain access to
information or shut down a service. For this reason, the
cloud should include a denial of service (DOS) protec-
tion. One way of enforcing DOS protection is done by
improving the infrastructure with more bandwidth and
better computational power which the cloud has abun-
dantly. In the more traditional sense, it involves filtering
certain packets that have similar IP source addresses or
server requests. The next issue concerning the cloud pro-
vider to end users is transmission integrity. One way of
implementing integrity is by using secure socket layer
(SSL) or transport layer security (TLS) to ensure that the
sessions are not being altered by a man in the middle
attack. At a lower level, the network can be made secure
by the use of secure internet protocol (IPsec). Lastly, the
final middle point between end users and the cloud is
transmission confidentiality or the guarantee that no one
is listening on the conversation between authenticated
users and the cloud. The same mechanisms mentioned
above can also guarantee confidentiality [18].
2.9. Related Works
Identity federation is evolving to meet business global-
ization strategies, enterprise and cloud service providers
are looking for best practices related to the cloud com-
puting environment. In their paper, the authors demon-
strated how remote access, identity management, and
security can work together to enable, secure, and inte-
grate cloud computing services. Four patterns were pro-
posed and implemented. With the use of integration pat-
terns, the enterprise can effectively design identity fed-
eration solutions in a hybrid cloud environment for dif-
ferent use cases specific to the business. Our critical
study on the proposed patterns enables us to draw our
conclusion that this work will give room for credential
compromise or theft [9].
Adoption of IDM in cloud computing environments
imposes challenges. The complexities that may be ex-
perienced by the enterprise in the management of ID
couple with the other factors have over head costs. Ac-
cording to [18] IDM IaaS is user centric identity man-
agement and is being considered as a complete all-round
solution addressing all possible issues of cloud IDMs.
The authors were of opinion that it should be outsource
to other companies that can effective manage them. Our
view on this work is that IDM IaaS may not be enough to
Copyright © 2011 SciRes. IJCNS
address this security challenges, because the paper did
not consider the other models like PaaS and SaaS. These
two models also require appropriate IDM. Since cloud
computing environments require holistic security, pri-
vacy and trust approach to earnest the benefits derivable
from cloud computing.
3. Theoretical Framework
The development of user identity management protocol
intends to answer some questions being asked by stake-
holders and developers. Some these questions are on
authorization, authentication, encryption, key manage-
ment identity provisioning etc. We attempt these ques-
tions in our architecture and the U-IDM protocol devel-
oped. Our approach in solving these challenges that
raised some questions is to develop a “user identity
management protocol that will involve stage by stage
transactions’ verification of the customers. We consid-
ered authentication, authorization and accounting (AAA)
in developing this protocol. These 3A are crucial to the
implementation of any protocol in cloud computing en-
vironments. Figure 2 describes our U-IDM protocol. The
stakeholders work together to achieve successive trans-
actions by monitoring the security of their infrastructural
networks. The stakeholders are cloud service providers,
registry, metering, billing, and customers. Bank and ISPs
and others are not left out.
3.1. Cloud Services’ Providers
The cloud services’ providers determine conditions to
release/provide any service. The security and IDM of the
services’ providers must be provided at different levels.
The organizations registering their companies with ser-
vice providers must have good service level agreements
(SLAs) to prevent intrusions. The employee of any or-
ganization representing such organizations must be pro-
vided with adequate identifiable attributes that can be
used to trace in case of any security bridge. Hence, end
to end security must be maintained. The services’ pro-
viders relate well with the registry. The unit authorizes
the release of any service(s).
3.2. Cloud Services’ Registry
The cloud services’ registry registers all available ser-
vices in the cloud computing environments. The regis-
tries maintain all the services and make them available to
the customers. The services’ providers determine the
services to release to the customers. The registry consults
with the services’ metering unit to determine the pay-
ment indices.
Figure 2. User identity management protocol architecture.
3.3. Cloud Services Metering
This unit provides all necessary parameters or formula to
determine what a customer will pay on the service being
requested for. The service type will be provided by reg-
istry unit. The services’ details will be prepared and send
to the billing unit.
3.4. Cloud Services Billing
This unit prepares the bill that the customer will pay.
This information will be sent to the customer through
service provider.
3.5. Cloud Services Customers
Customer get the bill make the payment through the bank
and the bank sends the payment confirmations to the
service provider.
3.6. Banks
Banks play significant in any transactions. Banks repre-
sent all of them in term fund raising and payment. Today,
online banking make business easier through the Internet
service providers or network operators.
3.7. NOs/ISPs
The Internet service providers or network operators are
pivot that determine the direction of every transactions
today. At every level, they should provide adequate se-
Having discussed the functions and relationships be-
tween stakeholders, Figure 3 is the user identity man-
Copyright © 2011 SciRes. IJCNS
Copyright © 2011 SciRes. IJCNS
agement protocol. The protocol shows the relationship
and transactions among the stakeholders. In addition,
Figure 4 explains the layers developed to support this
protocol. The physically layer has provision for time
sensitive/insensitive applications by providing TCP/UDP
transmissions options. The network layer takes care of
different network connections that may be used by the
customers i.e. GSM operators and Internet service pro-
viders. At this layer, a common protocol is adopted
thereby allow effective and good quality of services to
the customers. The network operators provide appropri-
ate security measures. This is to prevent system vulner-
ability, threats and attacks. Here verification take place,
hardware and software are authenticated before it is be-
ing transmitted to the application layer. Also, integration
of other security software is used at this layer. The use
DIDS/NIPS, anti-virus and possibly Firewalls at this
level is crucial to the successful of services’ delivery and
quality of service in the cloud computing environments.
4. Algorithm
(Pattern Matching) P and T are strings with lengths R and
S, respectively and are stored as arrays with one charac-
ter per element. This algorithm finds the INDEX of P in T.
1) [initialize]. Set K:= 1 and MAX := S – R + 1.
2) Repeat Steps 3 to 5 while K MAX:
3) Repeat for L = 1 to R: [Tests each character
of P].
If P[L] T[K + L - 1], then Go to Step 5.
[End of inner loop].
4) [Success]. Set INDEX = K, and Exit.
5) Set K := K + 1.
[End of Step 2 outer loop].
6) [Failure]. Set INDEX = 0.
7) Exit.
Cloud service
rovider Cloud services’ registr
Cloud services meteringCloud services billingCloud customers
os /ISPs
4, 5
1: customer sends request to cloud service provider through ISPs
2: authenticate (verify) customer’s device/attributes and forward the request to the provider
3: cloud service provider authenticates the customer and forwards the request to cloud services’ registry for provisioning and service confirmation
4: cloud services’ registry send the request to the cloud services’ metering unit to determine the cost implications
5: the metering unit sends the cost implications back to services’ registry
6: services’ registry sends it to service provider
7: service provider forward the request to the billing section
8: billing section determines the amount to be paid and send it back
9: service provider forward the amount and other payment detail information to the customer
10: customer returns payment details to the service provider
11: service provider sends the payment details to the bank
12: the bank acknowledges the payment details and sends the confirmation to the service provider
13: service provider sends the payment confirmation to the services’ registry
14: services’ registry authorized the transaction and provides the service to the customer.
Figure 3. User identity protocol stakeholders’ relationship.
Figure 4. User identity management protocol lay
. S
e simulate the algorithms using Table 1 below. Dif-
. Results and Discussion
he results show that when 100 tests were performed for
. Conclusion and Future Work
e presented U-IDM protocol that will accommodate all
Table 1. Customer attributes.
ferent organizations employees’ attributes were tested
character by character to determine the successful match
rate (SMR) failed match rate (FMR). This illustrates
those services’ providers that have weak, strong and very
strong IDM in their end. This test is important for cloud
customers to determine what levels of SLAs to agree
the successful and failed attributes. The weak has higher
percentage of failure and less percentage of success. The
weak has about 4.5% fail and about 2.7%. Below 40 tests
are not considered to be significant. They were used as
control experiments. These are illustrated in Figures 5
and 6.
the stakeholders. The algorithm used checks the custo-
mer attributes character by character. The simulations’
results for weak, strong and very strong show that failed
match rate and successful match rate have a wide margin.
Figure 5. The successful attributes tests.
Figure 6. Failed attributes tests.
Considering es from dif-
rent organizations, Figure 5 has about 2.7% match rate
A Short Introduction to Cloud Platforms
ell and Associ-
ates, San Francisco, 2008, pp. 1-13.
when we test for 100 employe
for weak IDM and Figure 6 has 4.5% match rate. We
proposed that every participants of cloud computing
must develop their own U-IDM. In future, we will work
on the billing scheme for the cloud computing services.
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