Authentication Mechanism for Private Cloud of Enterprise. Abstract

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Authentication Mechanism for Private Cloud of Enterprise

Mei-Yu Wu*, and Shih-Pin Lo

Department of Information Management, Chung Hua University, Hsinchu, Taiwan {mywu, e10010008}


Enterprises need accurate and efficient reaction speed in their business processes. There are diversity information needs in different departments, locations, or offices around the world. When enterprises adopt private cloud and consider the cost condition, SSL VPN (Secure Sockets Layer Virtual Private Network) gateway is a possible solution. Integrating internal enterprise resource planning application to build a private cloud, the external users of company may use mobile device to access control resources at any time and any place, as long as the network. The main purpose of this research is to achieve the authentication for private cloud of enterprise. The proposed approach adopts three-layers authentication, namely (1) using AD/LDAP to authenticate the user id and password (2) using dynamic password generated from MOTP Token to improve authentication (3) using device fingerprint verification to confirm that the mobile device was pre-authenticated. Based on the proposed three-layer authentication, the information security of company could be achieved and further increasing the feasibility of enterprises to adopt enterprise private cloud.

Keywords: Cloud Computing, Authentication, Private Cloud, Secure Sockets Layer Virtual Private Network (SSL VPN) Gateway




The purpose of implementing private cloud for enterprise is to provide existing information system functions and wants to continue the previous application and reduce upfront investment costs. Cloud computing provides employees the required software service at any time and any place. Employees cloud handle business at any time and any place, as long as the place where the network can be connected back to the company. But the important issue of private cloud is the authentication and access control. Existing security mechanism of private cloud in enterprise is merely to match username and password. However, only username and password authentication is not enough. If the account and password leak, any person may use any device to access enterprise resource.

Therefore, this research proposes an authentication mechanism for enterprises when they adopt private cloud. The research combined mobile one time password (MOTP) and device fingerprint to enhance the authentication. This study adopted unpredictable, not duplicate, and used only once dynamic password, and further combine information confirmed of important parts of device to reach complete authentication and access control. The proposed authentication mechanism will enhance the security of private cloud for enterprises.

The remainder of this paper is organized as follows. Section 2 reviews related works on cloud computing, server virtualization, SSL VPN Gateway and SSL VPN Gateway for cloud computing. Section 3 introduces the proposed authentication mechanism for private cloud. A complete analysis of proposed authentication mechanism is offered in Section 4. Finally, Section 5 presents our conclusions.


Related Works

2.1 Cloud Computing

The emergence of the phenomenon commonly known as cloud computing represents a fundamental change in the way information technology (IT) services are invented, developed, deployed, scaled, updated, maintained and paid for [8]. According to the definition of National Institute of Standards and Technology (NIST), cloud computing is a model for enabling convenient, on-demand network access to a share pool of configurable computing resource that can be rapidly provisioned and released with minimal management effort or service provider interaction [7][18].

The deployment models of cloud computing includes private cloud, public cloud, community cloud, and hybrid cloud [1][4][6][12]. Public cloud is the main model of cloud service. Multiple users share the applications, storage, and other resources provided by a service provider. Users do not need to construct the information infrastructure by self and

pay-per-usage. The disadvantage is the lack of complete control of data, network and security. Private cloud allows enterprises to take complete control of cloud computing resources. Cloud computing resource cloud be constructed by enterprise or service provider to enhance the performance, availability, and security. Community cloud shares infrastructure between several organizations from a specific community. It is suitable for academic institution with sharing data to joint venture. Hybrid cloud is a composition of public cloud and private cloud. Enterprise use services in private cloud and use public cloud computing resources to meet temporary needs [9][11][17][18]. 2.2 Server Virtualization

In general, the fastest way to implement a private cloud in enterprise is to make server virtualization. When implementing server virtualization, enterprise may use performance monitoring tool to record the physical average and peak values of CPU, memory, network, and disk I/O resources of servers. In the early evaluation stage, enterprise will collect related data at least one to two weeks to understand the current status of system performance. However, heavier system loading server is not suitable for virtualization [13][14][15]. The comparison table of after and before virtualization is illustrated in Table 1.

Table 1. Comparison of after and before virtualization

Item before

virtualization after virtualization

Cost of Server Procurement

The quantity of physical server is high. High cost of

hardware and electricity power consuming. Multiple servers simplify into virtual machines. Saving hardware and electricity cost. Utilization of hardware resource Resource utilization uneven Improve hardware resource utilization Deployment Time

Need to wait hardware procurement


Rapid deploying new servers in a few minutes. Variability of

hardware resource not easy easier Maintenance cost Not easy to


Reducing legacy maintenance costs

2.3 SSL VPN Gateway

SSL is abbreviation of secure socket layer. The main purpose of SSL is to provide confidential and reliability between two communication applications [2][3][5]. There are three mainly characteristics of secure connections provided by SSL, that is privacy, identification, and reliability.

In recent years, enterprises want to get convenient and flexible information infrastructure through the cloud computing. However, information security issue of cloud computing has been one of the threshold for enterprise to adopt cloud computing. In order to solve the cloud security issues, enterprises


began to deploy private cloud. SSL virtual private network (VPN) gateway is a solution for enterprise to securely access private cloud services [16]. There are two main types of SSL VPN gateway, i.e. SSL Portal VPN and SSL Tunnel VPN.

IT administrators may integrate existing account of active directory (AD) or lightweight directory access protocol (LDAP) to SSL VPN gateway. Therefore, IT administrators can easily configure SSL VPN gateway to control the different groups of users which can use what kind of resources and applications. Besides, SSL VPN gateway provides mobile one-time password (MOTP) to enhance security authentication [10].


Authentication Mechanism for Private


3.1 System Architecture

The research proposed an authentication mechanism for private cloud of enterprise. The system architecture is illustrated in Figure 1.

Figure 1. System Architecture

There are five main components in the system architecture and the detail description of each component is as the following.

(1) External Mobile Device User

Users from public cloud or private cloud use browser of mobile device or app to login the SSL VPN gateway. The dotted line means wireless connection by mobile devices.

(2) Firewall

Firewall is set up before SSL VPN gateway. Besides, SSL VPN may be established in demilitarized zone (DMZ) of firewall. If attackers attack the server, the internal network of enterprise will not be affected.

(3) SSL VPN Gateway

When users want to use the resource in the internal server, the SSL VPN gateway will check the authentication license of users. The SSL VPN gateway records the authorized applications and resource for users and log connection activities and login time of users.

(4) 3-Layers Authentication

In the research, we propose 3-layers

authentication including LDAP and AD

authentication, mobile one time password

authentication, and device fingerprint. The detail description of 3-layers authentication mechanism is described in next subsection.

(5) Terminal Server and MOTP Server

When external mobile device user connects to private cloud, MOTP server will give user a mobile one time password, i.e. the second layer authentication, MOTP, to allow user to verify third layer authentication, i.e. device fingerprint.

3.2 3-Layers Authentication

The proposed authentication mechanism for private of enterprise include three layers, which is LDAP and AD authentication, mobile one time password authentication, and device fingerprint. The detail description of 3-layers authentication mechanism is described in next subsection.

(1) LDAP and AD authentication

When users use browsers, such as Internet Explorer, Chrome, or Firefox, or app program, such as download from apple store or android play, LDAP and AD of SSL VPN gateway will verify the account and group. SSL VPN gateway will use SSL encryption technology to encode the input data to enhance the security.

(2) Mobile one time password (MOTP)

When users finish the first layer authentication, SSL VPN gateway will connect to MOTP server to process the second layer authentication. MOTP server will send a short message service (SMS) with random authentication code according to the original verified device. When user input the correct authentication code, the third authentication mechanism will be processed. The detail second layer authentication mechanism is shown in Figure 2.

Figure 2. The Second Layer Authentication Mechanism

(3) Device fingerprint

The third layer authentication is device fingerprint. The main purpose of this authentication stage is to verify whether the device is registered in the database of the SSL VPN gateway. SSL VPN gateway will scan the related information of mobile device, i.e. device fingerprint. IT administrator may define the scan rules, like only check the status or must be consistent with the original registered device


fingerprint. Possible device fingerprint includes CPU, memory, solid state drive (SSD), network card, and operating system version and so on.


Analysis of Proposed Authentication


According to the definition of domain 12 defined by the cloud security alliance (CSA), there are three

main specifications named identity

provisioning/deprovisioning, authentication, and authorization and user profile management [12]. This study adopted these specifications to analyze effectiveness assessment of the proposed 3-layers authentication mechanism.

(1) Identity provisioning/deprovisioning

When enterprises use cloud computing services, one of the main challenges is cloud security and timely management of existing staff, i.e. provisioning, in other words, create, and update accounts, and outgoing staff, i.e. deprovisioning, in other words, canceled, or deleting user accounts. Traditional SSL VPN gateway cannot make share unique identity user. In contrast, this study proposed three-layer authentication mechanism that will be able to identify the user uniqueness.

(2) Authentication

When enterprises began to use cloud services, reliable and easy managed authentication is a crucial requirement. Authentication mechanisms of traditional SSL VPN gateway cannot provide MOTP and device fingerprint verification. The authentication mechanism proposed in this research included MOTP and device fingerprint verification, so that enterprises will achieve into more rigorous access control of private cloud.

(3) Authorization and user profile management The requirement of authorization and user profile management is depending on whether the user is acting in its own name. Traditional SSL VPN gateway architecture did not set group policy to define what the user can use the application for authorization and user profile management. SSL VPN gateway defined in this research provides group policy. When the user login the home page, the system recognize what group the user belong to and what application user can use. The proposed authentication follows the identity and access management specified by CSA to achieve confidentiality, integrity, and available.


Conclusions and Future Works

After importing enterprise private cloud, make ensure the confidentiality, integrity and availability of transferred information is an important issue. Both of SSL VPN and virtualization cloud import private cloud for enterprise. Compared to the virtualization technology, SSL VPN has advantages, such as easy implementing, without further acquired servers and changing the existing structure. The research proposed three layers authentication mechanism for

private cloud of enterprise, including LDAP and AD authentication, MOTP authentication, and device fingerprint. The proposed authentication mechanism will enhance the security of private cloud for enterprises.

The access control of existing SSL VPN gateway still needs to overcome. In addition to the proposed three layers authentication mechanism, researchers may combine other access control mechanisms to enhance the authentication and access control for private cloud of enterprise.


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Table 1. Comparison of after and before  virtualization

Table 1.

Comparison of after and before virtualization p.2
Figure 1. System Architecture

Figure 1.

System Architecture p.3
Figure 2. The Second Layer Authentication  Mechanism

Figure 2.

The Second Layer Authentication Mechanism p.3