Privacy Preserving Personalized Access Control Service at Third Service Provider

: The discretionary access controls in today's computer systems are designed to enforce a specific access control policy. An application whose access control policies do not easily match the policy that is wired into the system is forced to work around that wired-in policy. As a result, the application itself must enforce discretionary security and cannot make use of the assurances of the computer system's discretionary access controls. This report presents a flexible approach to discretionary access control that allows the implementation of arbitrary access control policies. The generality of the approach allows a user to implement a discretionary access control policy that is tailored to an application, rather than having to work around a specific policy that is wired into the computer system. The report focuses on discretionary controls for object-oriented systems. Object-oriented systems are an emerging technology of great import for applications in business, industry, and the military. Many of these applications must share information among users with different needs and authorizations. The specific access rules desired will vary from application to application. Thus, a flexible approach to discretionary access control for such systems is proposed.

Access control (AC) is a computer security requirement used to control, in a computing environment, what the user can access, when and how. Policy administration is an essential feature of an AC system. As the number of computers are in hundreds of millions, and due to the different organization requirements, applications and needs, various AC models are presented in literature, such as: Discretionary Access Control (DAC), Mandatory Access Control (MAC), Role Based Access Control (RBAC), etc. These models are used to implement organizational policies that prevent the unauthorized disclosure of sensitive data, protecting the data integrity, and enabling secure access and sharing of information. Each AC model has its own methods for making AC decisions and policy enforcement. However, due to the diversity of AC models and the various concerns and restrictions, its essential to find AC metamodels with higher level of abstraction. Access control metamodels serve as a unifying framework for specifying any AC policy and should ease the migration from an AC model to another. This study reviews existing works on metamodels descriptions and representations. But, are the presented metamodels sufficient to handle the needed target of controlling access especially in the presence of the current information technologies? Do they encompass all features of other AC models? In this paper we are presenting a survey on AC metamodels.

ABSTRACTSome specific information or resources only can be accessed by authorized users. Discretionary access control (DAC), mandatory access control (MAC), and role‐based access control (RBAC) are three main classes of access control policies. MAC and RBAC are more secure than discretionary access control because a system instead of an object's owner determines the policy. MAC is appropriate for multilevel applications with high security requirements such as military ones, while RBAC provides security and business benefits. Most institutions, companies, and governments are multilevel, so relationships between roles or security levels tend to be hierarchical. In this work, an access control mechanism, providing explicit transitive exception and antisymmetric arrangement, is proposed to provide flexible and appropriate solutions to hierarchical relationships. For practicability, no access control policy is strictly constrained in the proposed mechanism such that security classes can be determined according to specific requirements. The proposed mechanism employs an elliptic curve cryptosystem and a two‐layer hash approach to ensure security and computation efficiency. Copyright © 2014 John Wiley & Sons, Ltd.

Traditional access control mechanisms prevent illegal access by controlling access right before executing an action; they belong to a class of a priori security solutions and, from this point of view, they have some limitations, like inflexibility in unanticipated circumstances. By contrast, a posteriori mechanisms enforce policies not by preventing unauthorized access, but rather by deterring it. Such access control needs evidence to prove violations. Evidence is derived from one or several log records, which trace each user's actions. Efficiency of violation detection mostly depends on the compliance of log records with the access control policy. In order to develop an efficient method for finding these violations, we propose restructuring log records according to a security policy model. We illustrate our methodology by applying it to the healthcare domain, taking care of the IHE (Integrating the healthcare enterprise) framework, particularly its basic security profile, ATNA (Audit Trail and Node Authentication). This profile defines log records established on the analysis of common health practice scenarios. We analyze and establish how ATNA log records can be refined in order to be integrated into an a posteriori access and usage control process, based on an expressive and contextual security policy like the OrBAC policy.

Several existing access control solutions mainly focus on preserving confidentiality of stored data from unauthorized access and the storage provider. Moreover, to keep sensitive user data confidential against untrusted
\nservers, existing solutions usually apply cryptographic methods by disclosing data decryption keys only to authorized users. However, these solutions inevitably introduce a heavy computation overhead on the data owner
\nfor key distribution and data management when fine-grained data access control is desired. In addition, access
\ncontrol policies as well as users’ access patterns are also considered as sensitive information that should be
\nprotected from the cloud. In this paper, we propose PAbAC, a novel privacy preserving Attribute-based framework, that combines attribute-based encryption and attribute-based signature mechanisms for securely sharing
\noutsourced data via the public cloud. Our proposal is multifold. First, it ensures fine-grained cryptographic access control enforced at the data owner’s side, while providing the desired expressiveness of the access control
\npolicies. Second, PAbAC preserves users’ privacy, while hiding any identifying information used to satisfy
\nthe access control. Third, PAbAC is proven to be highly scalable and efficient for sharing outsourced data in
\nremote servers, at both the client and the cloud provider side.

Enormous popularity of Social Networking Sites has introduced a great number of privacy risks.Even the most popular of all the social networking sites have characterized access control policies in terms of explicit tracking of the interpersonal relationships between the subjects, objects and their inter relation.In this paper we present a novel paradigm that accounts for a secure, yet sociable information flow model based on access control policies.We took advantage of real time success of the access control security policies in operating systems by implementing them on online social networks at the mandatory level so that the user's privacy does not have to be at stake by the growth of social network and activities or by the level of user understanding of the privacy settings provided by the social networking sites based on discretionary access control.We used Facebook and Google+ as case study and implemented the security policy in SecureWall to mitigate possible privacy leakage scenarios observed.We have implemented Chinese wall policy for community level privacy, Bell la-Padulla access control model to assure confidentiality to the user and Biba Access control model for providing Integrity.Since Bell la-Padulla and Biba models are basically meant to serve military security and therefore can risk sociability, we have combined the two models using Lipner Security Matrix in order to provide security without risking sociability.Our research can be adopted by online social networking sites for the mandatory level security especially for social networking in organizational specific activities.

Towards more pro-active access control in computer systems and networks

Healthcare information systems deal with sensitive data across complex workflows. They often allow various stakeholders from different environments to access data across organizational boundaries. This elevates the risk of exposing sensitive healthcare information to unauthorized personnel, leading ‘controlling access to resources' a major concern. To prevent unwanted access to sensitive information, healthcare organizations need to adopt effective workflows and access control mechanisms. Many healthcare organizations are not yet considering or do not know how to accommodate the ‘context' element as a crucial element in their workflows and access control policies. The authors envision the future of healthcare where ‘context' will be considered as a crucial element. They can accommodate context through a new element ‘environment' in workflows, and can accommodate context in policies through well-known attribute based access control mechanism (ABAC). This research mainly addresses these problems by proposing a model to integrate workflows and access control policies and thereby identifying workflow activities that are not being protected by access control policies and improving the workflow activities and/or existing access control policies using SARE (Subject, Action, Resource, and environment) elements.

Healthcare information systems deal with sensitive data across complex workflows. They often allow various stakeholders from different environments to access data across organizational boundaries. This elevates the risk of exposing sensitive healthcare information to unauthorized personnel, leading ‘controlling access to resources' a major concern. To prevent unwanted access to sensitive information, healthcare organizations need to adopt effective workflows and access control mechanisms. Many healthcare organizations are not yet considering or do not know how to accommodate the ‘context' element as a crucial element in their workflows and access control policies. The authors envision the future of healthcare where ‘context' will be considered as a crucial element. They can accommodate context through a new element ‘environment' in workflows, and can accommodate context in policies through well-known attribute based access control mechanism (ABAC). This research mainly addresses these problems by proposing a model to integrate workflows and access control policies and thereby identifying workflow activities that are not being protected by access control policies and improving the workflow activities and/or existing access control policies using SARE (Subject, Action, Resource, and environment) elements.

Chapter 23 - Policies, Access Control, and Formal Methods

One of the security issues in data outsourcing scenario is the enforcement of data owner's access control policies. This includes some challenges; namely, the number of keys required to access authorized resources, efficient policy updating, write access control enforcement, user and data owner overhead, and preserving confidentiality of data and policies. Most of the existing solutions address only some of the challenges, while they impose high overhead on both the data owner and users. Though, policy management in the Role-Based Access Control (RBAC) model is easier and more efficient due to the existence of role hierarchical structure and role inheritance; most of the existing solutions address only enforcement of policies in form of access control matrix. In this paper, we propose an approach to enforce RBAC policies on encrypted data outsourced to service provider (SP). We utilize Chinese Remainder Theorem (CRT) for key management and role/permission assignment. Efficient user revocation, support of role hierarchical structure updates, availability of authorized resources for users of newly added roles, and enforcement of write access control policies as well as static separation of duties (SSD), are of the proposed solution advantages. In addition, the ciphertext size is linearly proportional to the plaintext size, regardless of the number of roles and users.

The Pi-calculus has been developed to reason about behavioural equivalence. Different notions of equivalence are defined in terms of process interactions, as well as the context of processes. There are various extensions of the Pi-calculus, such as the SPI calculus, which has primitives to facilitate security protocol design.<br /> <br />Another area of computer security is access control research, which includes problems of access control models, policies and access control mechanism. The design of a unified framework for access control requires that all policies are supported and different access control models are instantiated correctly.<br /> <br />In this paper we will utilise the Pi calculus to reason about access control policies and mechanism. An equivalence of different policy implementations, as well as access control mechanism will be shown. Finally some experiences regarding the use of Pi-calculus are presented.

Many existing software systems like logistics systems or enterprise applications employ data security in a more or less ad hoc fashion. Our approach focuses on access control such as permission-based discretionary access control (DAC), variants of role-based access control (RBAC) with delegation, and attribute-based access control (ABAC). Typically, software systems implement hybrid access control making an effective security analysis and assessment rather difficult. We propose an analysis methodology to reconstruct access control using a novel modular access control model. Our modular approach allows us to flexibly model exactly those access properties that are relevant for a given system. As formalism we use the Object Constraint Language (OCL) with Ecore from the Eclipse Modeling Framework (EMF). We demonstrate the suitability of our access control model for three software systems: a port community system (PCS), a clinical information system (CIS), and an identity management system (IdMS). For the PCS and CIS we model concrete roles and policies. For the IdMS we evaluate our analysis methodology in-depth by reconstructing access control policies from byte code using the Soot analysis framework as well as model transformation techniques (QVTo). The resulting model helped us to identify design deficiencies. Violated OCL invariants such as for mutually exclusive roles or cardinality constraints revealed non-trivial security vulnerabilities.

PurposeThis paper aims to manage access control tasks to satisfy the user privacy needs of online information resources according to social relations and tags.Design/methodology/approachThe study proposes a method for access control management in the online social context. The proposed method includes the access control policy management process, metadata of access control policies, the data of ontologies, tags, and social relations, and conflict detection rules.FindingsOnline information sharing and hiding, which needs to consider social relations and mentioned topics, is a unique context and needs a novel access control mechanism. Ontologies are powerful and expressive enough to identify conflicts in access control policies. The paper provides a method using ontologies to control the access control activities based on social relations and tags on web content. The effectiveness of the method's conflict detection rules is validated through several scenarios.Research limitations/implicationsTo make the proposed method suitable for widespread usage, further work is required to develop an access control policy specification and conflict detection tool. The proposed method introduces relatively novel usage scenarios, which consider social relationships, and tags compared with existing access control methods for online information sharing.Practical implicationsThe proposed access control mechanism can be integrated into existing web sites. Online users can use this method to share information more easily than at present.Originality/valueThe method enables flexible access control in social contexts and handles unavoidable conflicts. It also opens the way to new access control scenarios in online social activities. The method can be used to keep secrets hidden from selected people.

Access control is a security technique that specifies which users can access particular resources in a computing environment. Over the years, numerous access control models have been developed to address various aspects of computer security. In this paper, we focus on a modern approach, attribute-based access control (ABAC), which has been proposed in order to overcome limitations of traditional models: discretionary access control (DAC), mandatory access control (MAC) and role-based access control (RBAC). The work on integrating access control mechanisms in semantic web technologies is developing into two directions: (1) to use semantic web technologies for modeling and analyzing access control policies and (2) to protect knowledge encoded in an ontology. In this paper we focus on the first issue and investigate how ABAC can be integrated into ontology languages.