Access control: principle and practice

Chapter 23 - Policies, Access Control, and Formal Methods

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.

In early 1970s the access matrix model for the security of software system was developed [1,2] as a generalized description of operating system protection mechanisms. This matrix is called security matrix, the columns of the matrix represent to some data structures in the system, the rows of the matrix are those potential users of the system, and each element in the matrix is a protection decision, d(i,j), specifying rule that governs the manipulation of the data structure j by user i. The users of the system may be permitted any of a number of different access rights to a data structure such as reading, appending, updating, deletion, execution, and changing protection. A modified access matrix model is used in MULTICS [3] and other virtual memory system.Later in 1984, an access control with single key-lock system was developed [4]. The system involved three matrices namely, assessors key matrix, information locks matrix, and access matrix. Each user has only one key associated with unique lock for each file. For each user and each file there is an access code that represented the permission of user to own, to write, to read, to execute, or not to access the file. The entries of these matrices are non-negative integers and stored in the main memory. However, for a large system that might involve hundreds or thousands of users and a huge number of files. Then, a large memory space is occupied by these three matrices.This research proposes a new technique that converts a number of matrix entries (at least 10) into a rational number and then stored in the memory. When access is requested the appropriate rational number is decoded, through a program, into the unique original matrix entries for the key-lock system to control access of information.The advantages of this new method are: (1) The reduction of the memory space required for the keys, locks, and access codes is at least 80% of the original needs. (2) The techniques of encoding and decoding are simple. (3) The construction of keys and locks still remain as simple as those proposed in [4]. Procedures for encoding and decoding are included and examples are presented.

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.

Business Processes for Web Services are the new paradigm for the lightweight integration of business from different enterprises.Whereas the security and access control policies for basic web services and distributed systems are well studied and almost standardized, there is not yet a comprehensive proposal for an access control architecture for business processes. The major issue is that a business process describe complex services that cross organizational boundaries and are provided by entities that see each other as just partners and nothing else.This calls for a number of differences with traditional aspects of access control architectures such as• credential vs classical user-based access control,• interactive and partner-based vs one-server-gathers-all requests of credentials from clients,• controlled disclosure of information vs all-or-nothing access control decisions,• abducing missing credentials for fulfilling requests vs deducing entailment of valid requests from credentials in formal models,• "source-code" authorization processes vs data describing policies for communicating policies or for orchestrating the work of authorization servers.Looking at the access control field we find good approximation of most components but not their synthesis into one access control architecture for business processes for web services, which is the contribution of this paper.

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.

Background: Cloud computing provides access to a large scale of resources. Access control is the indispensable requirement for protecting cloud resource. A cloud service provider is responsible for enforcing access control and they normally rely upon conventional access control mechanisms. Methods: These access control policies, consider the access control primitives in separation which may lead to abuse of access control. These aforesaid problems motivated our research to center around the provision of access control by considering the association among the three access control primitives namely the user making access request, resource upon which access is requested and operation performed by the user on the resource. Hence Ontology Centric Access Control (OCAC) is being proposed in this paper. Findings: This OCAC circulates authorization rules among the primitives of access control say subject, object and action by reducing the various associations among the associations among the access control elements; it is observed that there is less chance for security violation. Ontology is used since it reduces the times of agreement while exchanging the authorization policies across the security domains. For reducing the number of statements and rules in policy base, subsumption property is used. This reduces the space and time complexity. Applications/Improvements: We are applying our work to protect bank data as banks are embracing clouds to store huge data by cutting their IT costs.Keywords: Access Control, Ontology, Cloud Computing, User Ontology, Resource Ontology, Activity Ontology Introduction

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

This paper first brief reviews the state of the security technology research and access control in the web service environment. Despite recent advances in access control approaches for Web Services, the heterogeneity of subjects and objects in Web Service environment has made it difficult to development of effective access control system. So we present a context-aware service-orient role-based access control model (CSRBAC). In CSRBAC model, access control system can make its access control decisions by capturing security relevant environmental context, such as time, location, operation state, or other environmental information. Based on CSRBAC model, a secure architecture model for Web Services is presented. It implements an access control system with dynamically grant and adapt permissions to users based on their current context. Compared to traditional access control mechanisms, the CSRBAC model can provide management flexibility and improved security for Web Services applications.KeywordsAccess ControlRole AssignmentContext ParameterPolicy Decision PointAccess Control SystemThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Traditionally, access control is enforced by centralized stand-alone architectures. In this case, the access controller “knows” all information necessary to evaluate the access control policy. As a consequence, when a subject sends a query to the access controller, this access controller does not need to interact with this subject to decide if this query must be accepted or rejected. However, in more recent architectures, such a centralized evaluation of the access control policy is no longer appropriate. When a subject sends a query to the access controller, this controller needs to interact with the subject through a negotiation protocol. The objective of this protocol is to exchange additional information necessary to evaluate the policy. This information generally correspond to credentials the subject has to provide to prove that he or she satisfies the requirements to execute the query. Notice that the negotiation protocol can actually behave in a symmetric way in the sense that the access controller may also exchange credentials to provide the subject with guarantees that this subject can interact securely with the controller. The objective of the negotiation is to exchange credentials in order to decide if the query must be accepted or not. When the access control policy corresponds to a set of permission rules, this consists in determining if the query matches one of these permission rules. However, the access control policy may also include prohibitions that act as exception to the permissions. In that case, the negotiation protocol must decide if (1) there is a permission to accept the query and (2) there is no prohibition that would apply to deny the query.

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.

Dynamically monitoring the state changes of an underlying system, detecting and reacting to changes without delay are crucial for the success of any access control enforcement mechanism. With their inherent nature, active (Event- Condition-Action or ECA) rules are prospective candidates to carry out change detection and to provide access control. Current systems or models do not provide a flexible mechanism for enforcing Role-Based Access Control (RBAC) standard and its extensions in a seamless way, and do not adapt to policy or role structure changes in enterprises, which are indispensable to make RBAC usable in diverse domains. In this paper we will show how On-When-Then-Else authorization rules (or enhanced ECA rules) are used for enforcing RBAC standard and its extensions such as generalized temporal RBAC, control flow dependency constraints, privacy-aware RBAC, and so forth in a seamless way. Furthermore, these rules also provide active security. Large enterprises have hundreds of roles, which requires thousands of rules for providing access control, and generating these rules manually is error-prone and a cognitive-burden for non-computer specialists. Thus, in this paper, we will discuss briefly how these authorization rules can be automatically (or semi-automatically) generated from high level specifications of enterprise access control policies. We will also discuss the implementation using Sentinel+, an active object oriented system.

Traditional access control models often assume that the entity enforcing access control policies is also the owner of data and resources. This assumption no longer holds when data is outsourced to a third-party storage provider, such as the cloud. Existing access control solutions mainly focus on preserving confidentiality of stored data from unauthorized access and the storage provider. However, in this setting, access control policies as well as users’ access patterns also become privacy sensitive information that should be protected from the cloud. We propose a two-level access control scheme that combines coarse-grained access control enforced at the cloud, which provides acceptable communication overhead and at the same time limits the information that the cloud learns from his partial view of the access rules and the access patterns, and fine-grained cryptographic access control enforced at the user’s side, which provides the desired expressiveness of the access control policies. Our solution handles both read and write access control.KeywordsAccess ControlAccess PatternCloud ProviderData OwnerAccess Control PolicyThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Indexing Policies in Cloud Information Accountability for Data Sharing presents a new way to supplement the current consumption and delivery model for IT services based on the Internet, by providing for dynamically scalable and often virtualized resources as a service over the Internet. Here, User Control Policies files and Access control policies files are indexed, and then only we can search the particular file easily. Cloud Information Accountability (CIA) framework, based on the notion of information accountability. One of the main innovative features of the CIA framework lies in its ability of maintaining lightweight and powerful accountability that combines aspects of access control, usage control and authentication. By means of the CIA, data owners can track not only whether or not the service-level agreements are being honored, but also enforce access and usage control rules as needed.. Access control policies and user control policies are spread across the cloud within the control of Cloud Service provider, the new user can enter their authorized login and fetch needed files, when these files are indexed. The integrity checks and oblivious hashing (OH) technique to our system in order to strengthen the dependability of our system in case of compromised JRE and also I updated to log records structure to provide additional guarantees of integrity and authenticity.

In this paper, a variety of cloud service combinations is used to form the control core of a smart home, realize data forwarding, storage, and analysis in the cloud, and complete the remote management of smart home devices. This paper studies the secure access control of smart home data combined with the blockchain technology and password technology to realize the secure and efficient access control of smart home data. The system can achieve the goal of independent research and development. Aiming at the problem that the access control of a smart home is generally managed by third‐party authorized institutions and there is an unauthorized access, a blockchain‐based smart home (BSH) access control scheme is proposed. The scheme extends the attribute‐based access control model (ABAC) and applies the blockchain technology to the smart home ABAC model to realize fine‐grained access control. In the scheme, the resource provider first publishes the access control policy of the resource to the blockchain. If the resource visitor wants to access the resource, he needs to submit an access request to the blockchain and use an SM2 threshold signature to process the transaction proposal. The endorsement peer node in the blockchain runs the access control policy smart contract to decide whether to grant access rights. This scheme can ensure that resource providers can participate in all the processes of access control and avoid the risk of unauthorized access caused by the centralized management of the third party. Finally, the simulation experiment is carried out on the Hyperledger Fabric alliance chain development platform. The results show that the BSH access control scheme has good applicability in the smart home scenario.