The main difference between cloud computing and traditional enterprise internal IT services is that the owner and the user of cloud IT infrastructures are separated in cloud. This change requires a security duty separation in cloud computing. Cloud service providers (CSP) should secure the services they offer and cannot exceed the customers' authorities. Currently, no traditional information security products can meet this requirement. A multi-tenancy trusted computing environment model (MTCEM) is designed for IaaS delivery model, and its purpose is to assure a trusted cloud infrastructure to customers. MTCEM presents a dual level transitive trust mechanism and supports a security duty separation function simultaneously. With MTCEM, CSP and customers can cooperate to build and maintain a trusted cloud computing environment. MTCEM can be used to improve customers' confidence on cloud computing. The prototype of MTCEM shows that it has low impact on system performance and it is technically and practically feasible.

A trusted computing environment model in cloud architecture

Traditional data leakage prevention strategies encompass access control, audit logon and authority management. They have some effects on preventing sensitive information from leakage, while the system’ s availability may be degraded seriously by their limitation. To solve this problem, a novel model based on Windows file system filter driver is proposed in this paper, in which system encrypts files automatically according to encryption strategies. Leaking confidential information out of enterprise environment, intentionally or unintentionally, will be prevented effectively. Moreover, it has the characteristic of mandatory and transparent encryption, which can compromise the contradiction between data security and user flexibility.

Research and Application of the Transparent Data Encpryption in Intranet Data Leakage Prevention

Network security is one of the major issues facing IS today. Securing a network from unauthorized intrusion and detecting unauthorized intrusion are vitally important to ensure that information on the network is free from malicious corruption. Preventing unauthorized access to a network is not always possible. Consequently, the ability to detect a network intrusion is of paramount importance. Log files are one of the means used by system administrators to detect intrusions. However, experienced hackers will often erase the log files. While this proves that network security has been penetrated, it leaves no details on how the hacker entered the system or what he accomplished. Even worse, the experienced hacker can replace the log files with a file showing normal network traffic flows. In this case, it is impossible to detect network intrusion using the log files. Therefore, the log files must be protected to be of any use in network security. This paper will discuss the best practices to use to secure the network system logs. The different methods will range from the least secure to the most secure, often depending on the number of safeguards being employed. These safeguards have been taken from academic research, current business implementations, and our own research.

Locking down log files: enhancing network security by protecting log files

In the cloud environment, owing to the large-scale sharing of the upper application instance and the underlying virtual machine resources, the tenants' information flow boundary in the shared virtual machine is fuzzy and difficult to identify. In addition, protection of tenant information flow between processes is inadequate, resulting in the leakage of sensitive information of tenants. Therefore, a dynamic control method for tenants' sensitive information flow based on virtual boundary recognition is proposed. By analyzing the behavior and operation log of tenants, the behavior feature vectors of tenants are constructed, and an automatic recognition algorithm of tenant virtual boundary based on the dynamic spiking neural network is designed. This algorithm can realize dynamic identification of the tenant virtual security boundary when the application service demand changes dynamically. Further, combined with the concept of centralized and decentralized information flow control, a dynamic control method of sensitive information flow is established. The security label is formally defined by using the lattice structure, and the control rules of tenants' information flow and the rules of tenant label encryption-declassification are designed. Thus, the independent, dynamic and secure control of tenants' information flow inside and outside the tenant virtual boundary. Finally, the detailed design of a dynamic security control application system for cloud tenants' sensitive information flow is provided. Experiments confirm that the proposed algorithm can identify the security boundary of tenants more accurately and efficiently than the traditional spiking neural network classification methods. Further, the security and effectiveness of the method is verified by the intransitive noninterference theory and the experiment of information flow control.

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Dynamic Control Method for Tenants’ Sensitive Information Flow Based on Virtual Boundary Recognition

The validity of the security policy has important impacts on the safety performance of network information system. For purpose of verifying it effectively, an assessment model of network security policy based on security capability is proposed. The relationship of defense methods, application targets, and information security attribute characteristics is analyzed based on the establishing of security domain and security policy, and the network security capability of security policy is evaluated. Result shows that the model can effectively reflect the protect ability of security policy. It provides a new solution and reference for assessing and adjusting the network security policy, so as to better ensure system security.

Assessment of Network Security Policy Based on Security Capability

Transitive Trust and Performance Analysis in Windows Environment

The Application of Information Leakage Defendable Model in Enterprise Intranet Security

A Noninterference-Based Trusted Chain Model

Security Protocol and Scheme for Inter-Realm Information Accessing

Tenant separation is a provision for cloud computing to be provided to tenants as a third party service, therefore the tenants' confidence in the security effectiveness of cloud tenant is critical to the promotion of cloud services. However, in a third party service such as cloud computing, tenants have few opportunities to take part in the construction and management of the infrastructure of cloud computing, making it hard for the tenants to trust the tenant separation mechanism in cloud. This paper views the transparency requirement as a part of trusted cloud tenant separation mechanism, implements a cloud tenant separation mechanism and its transparency requirement based on the inter-domain information flow control policy in cloud computing systems, and proves that the resulting cloud tenant separation mechanism is secure and effective by non-interference theory.

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Han Zhen

Papers

Transitive Trust and Performance Analysis in Windows Environment

The Application of Information Leakage Defendable Model in Enterprise Intranet Security

A Noninterference-Based Trusted Chain Model

Security Protocol and Scheme for Inter-Realm Information Accessing

Trusted Cloud Tenant Separation Mechanism Supporting Transparency