Vincent Hu

National Institute of Standards and Technology | NIST · Computer Security Division

Interrelated computing device’s system such as IoT, RFID, or edge device’s systems are pervasively equipped for today’s information application and service systems, protecting them from unauthorized access i.e. safety is critical, because a breach from the device may cause cascading effects resulting to data lost or even crash of the whole informat...

As big data, cloud computing, grid computing, and the Internet of Things reshape current data systems and practices, IT experts are keen to harness the power of distributed systems to boost security and prevent fraud. How can these systems’ capabilities be used to improve processing without inflating risk?

Access control (AC) is critical for preventing sensitive information from unauthorized access. Various AC systems have been proposed and enforced in different types of information systems (e.g., bank and military). However, existing AC systems cannot thoroughly address the challenges in emerging distributed processing systems (DPS), such as Big Dat...

Access control offers mechanisms to control and limit the actions or operations that are performed by a user on a set of resources in a system. Many access control models exist that are able to support this basic requirement. One of the properties examined in the context of these models is their ability to successfully restrict access to resources....

To ensure that an access control (AC) system is safe, there must be a reliable means to verify that the specified AC policy model conforms to the safety requirements and policy author's intentions. A general verification approach includes black-box and white-box testing, as well as the generation of sufficient test cases to check the correctness of...

Extensible Access Control Markup Language (XACML) and Next Generation Access Control (NGAC) are very different attribute based access control standards with similar goals and objectives. An objective of both is to provide a standardized way for expressing and enforcing vastly diverse access control policies in support of various types of data servi...

Attribute-based access control (ABAC) is a flexible approach that can implement AC policies limited only by the computational language and the richness of the available attributes, making it ideal for many distributed or rapidly changing environments.

In recent years, Attribute Based Access Control (ABAC) has evolved as the preferred logical access control methodology in the Department of Defense and Intelligence Community, as well as many other agencies across the federal government. Gartner recently predicted that “by 2020, 70% of enterprises will use attribute-based access control (ABAC) as t...

The cloud is a modern computing paradigm with the ability to support a business model by providing multitenacy, scalability, elasticity, pay as you go and self provisioning of resources by using broad network access. Yet, cloud systems are mostly bounded to single domains and collaboration among different cloud systems is an active area of research...

Access control (AC) policies can be implemented based on different AC models, which are fundamentally composed by semantically independent AC rules in expressions of privilege assignments described by attributes of subjects/attributes, actions, objects/attributes, and environment variables of the protected systems. Incorrect implementations of AC p...

The increased complexity of modern access control (AC) systems stems partly from the need to support diverse and multiple administrative domains. Systems engineering is a key technology to manage this complexity since it is capable of assuring that an operational system will adhere to the initial conceptual design and defined requirements. Specific...

Access control (AC) is one of the most fundamental and widely used requirements for privacy and security. Given a subject's access request on a resource in a system, AC determines whether this request is permitted or denied based on AC policies (ACPs). This position paper introduces our approach to ensure the correctness of AC using verification. M...

Mandatory access control (MAC) mechanisms control which users or processes have access to which resources in a system. MAC policies are increasingly specified to facilitate managing and maintaining access control. However, the correct specification of the policies is a very challenging problem. To formally and precisely capture the security propert...

Access control mechanisms are a widely adopted technology for information security. Since access decisions (i.e., permit or deny) on requests are dependent on access control policies, ensuring the correct modeling and implementation of access control policies is crucial for adopting access control mechanisms. To address this issue, we develop a too...

Attribute relations in access control mechanisms or languages allow accurate and efficient specification of some popular access control models. However, most of the access control systems including today's de-facto access control protocol and specification language, XACML, does not provide sufficient syntactic and semantic support for the specifica...

Access control mechanisms are used to control which princi- pals (such as users or processes) have access to which resources based on access control policies. To ensure the correctness of access control poli- cies, policy authors conduct policy verification to check whether certain properties are satisfied by a policy. However, these properties are...

As software systems become more and more complex, and are deployed to manage a large amount of sensitive in-formation and resources, specifying and managing correct access control policies is critical and yet challenging. Pol-icy testing is an important means to increasing confidence in the correctness of specified policies and their implemen-tatio...

Access control mechanisms control which subjects (such as users or processes) have access to which resources. To facilitate managing access control, policy authors increasingly write access control policies in XACML. Access control policies written in XACML could be amenable to multiple-duty-related security leakage, which grants unauthorized acces...

Access control policies are often specified in declarative languages. In this paper, we propose a novel approach, called mutation verification, to assess the quality of properties specified for a policy and, in doing so, the quality of the verification itself. In our approach, given a policy and a set of properties, we first mutate the policy to ge...

To formally and precisely capture the security properties that access control should adhere to, access control models are usually written to bridge the rather wide gap in abstraction between policies and mechanisms. In this paper, we propose a new general approach for property verification for access control models. The approach defines a standardi...

Access control is one of the most fundamental and widely used security mechanisms. Access control mechanisms control which principals such as users or processes have access to which resources in a system. To facilitate managing and maintaining access control, access control policies are increasingly written in specification languages such as XACML....

Many researchers have tackled the architecture and requirements aspects of grid security, concentrating on the authentication or authorization mediation instead of authorization techniques, especially the topic of policy combination. Policy combination is an essential requirement of grid, not only because of the required remote (or global) vs. loca...

Trust domain management for the global access of a grid is managed under centralized schema for most of the current grid architectures, which are designed based on the concept that there is only one grid for every grid member, therefore requiring central management for authentication and authorization. This design not only has its own limitations,...

In computer security, many researches have tackled on the possibility of a unified model of access control, which could enforce any access control policies within a single unified system. One issue that must be considered is the efficiency of such systems, i.e., what is the computational complexity for the enforceability validation of access contro...

As a major component of any host, or network operating system, access control mechanisms come in a wide variety of forms, each with their individual attributes, functions, methods for configuring policy, and a tight coupling to a class of policies. To afford generalized protection, NIST has initiated a project in pursuit of a standardized access co...

Many different access control policies and models have been developed to suit a variety of goals; these include Role-Based Access Control, Onedirectional Information Flow, Chinese Wall, Clark-Wilson, N -person Control, and DAC, in addition to more informal ad hoc policies. While each of these policies has a particular area of strength, the notation...

While intrusion detection systems are becoming ubiquitous defenses in today's networks, currently we have no comprehensive and scientifically rigorous methodology to test the effectiveness of these systems. This paper explores the types of performa nce measurements that are desired and that have been used in the past. We review many past evaluation...

Many different access control policies and models have been developed to suit a variety of goals; these include Role-Based Access Control, One-directional Information Flow, Chinese Wall, Clark-Wilson, N-person Control, and DAC, in addition to more informal ad hoc policies. While each of these policies has a particular area of strength, the notation...

Existing software infrastructures and middleware provide uniform security services across heterogeneous information networks. However few, if any, tools exist that support access control policy management for and between large enterprise information networks. Insiders often exploit gaps in policies to mount devastating attacks. This paper presents...

Portions of this document have been abstracted from other U.S. Government publications, including: “Minimum InteroperabilitySpecification for PKI Components (MISPC), Version 1” NIST SP 800-15, January 1998;“Certification Authority Systems”, OCC 99-20, Office of the Comptroller of the Currency, May 4, 1999; “Guideline for Implementing Cryptography i...