1. COS 80011 Web Application Architectures Lecture 10 Access Control

2. Outline What is Access Control?
4/6/2017
Outline
What is Access Control?
Access Control Matrix and Access Control List
Role-Based Access Control
User-Role Assignment
Role-Permission Assignment
Attribute-Based Access Control
Context-Aware Access Control
Context-Aware User-Role Assignment
Context-Aware Role-Permission Assignment
Swinburne University of Technology
Swinburne University of Technology 2

3. Outline What is Access Control?
4/6/2017
Outline
What is Access Control?
Access Control Matrix and Access Control List
Role-Based Access Control
User-Role Assignment
Role-Permission Assignment
Attribute-Based Access Control
Context-Aware Access Control
Context-Aware User-Role Assignment
Context-Aware Role-Permission Assignment
Swinburne University of Technology
Swinburne University of Technology 3

4. 4/6/2017
Access Control (I)
Access control is one of the fundamental security mechanisms
needed to protect computer resources (and/or services) against unauthorized access according to a security policy
policy – is a rule (who can access what)
verifying whether a subject (user) is allowed to carry out a specific action (operation) on an object (resource)
it is a mechanism to determine whether a request from a user to access resources in a system should be permitted or denied
Swinburne University of Technology
Swinburne University of Technology 4

5. Access Control (II) It has three major components
4/6/2017
Access Control (II)
It has three major components
subjects – represent the users in a system performing actions on an object
objects – represent the resources that are being protected by the system
operations – represent all the actions that the subjects can perform on the objects
Swinburne University of Technology
Swinburne University of Technology 5

6. Access Control (III) Access Control Models/Technologies
4/6/2017
Access Control (III)
Access Control Models/Technologies
Access Control Matrix or Access Matrix (AM)
Access Control List (ACL)
Role-Based Access Control (RBAC)
Attribute-Based Access Control (ABAC)
Context-Aware Access Control (CAAC)
Extended RBAC Models: TMAC (team), OrBAC (organization), …
ABAC Models: XACML, … …
Swinburne University of Technology
Swinburne University of Technology 6

7. Access Control (IV) Traditional forms of Access Control
4/6/2017
Access Control (IV)
Traditional forms of Access Control
AM, ACL, RBAC, …
file systems, operating systems, database systems, …
Access Control on the Web
XACML (OASIS standard Web-based AC), XACML for RBAC, …
Domain-specific inputs converted to the XACML Request Context.xml (PEP)
XACML core policy framework or XACML RBAC implementation using (J2SE, CORBA, etc.), resources are exposed as Web services (PDP, PIP, PAP)
XACML Response Context.xml is converted to the domain-specific outputs (PEP)
Swinburne University of Technology
Swinburne University of Technology 7

8. Outline What is Access Control?
4/6/2017
Outline
What is Access Control?
Access Control Matrix and Access Control List
Role-Based Access Control
User-Role Assignment
Role-Permission Assignment
Attribute-Based Access Control
Context-Aware Access Control
Context-Aware User-Role Assignment
Context-Aware Role-Permission Assignment
Swinburne University of Technology
Swinburne University of Technology 8

9. Access Control Matrix (I)
4/6/2017
Access Control Matrix (I)
Access Control Matrix or Access Matrix (AM)
access control technology has a long history that started in the late 60s
it was first introduced by Lampson in 1971, who introduced a formal, mathematical description of a basic access control model named Access Control Matrix
<Lampson, Butler W. (1971), Protection, Proceedings of the 5th Princeton Conference on Information Sciences and Systems>
Swinburne University of Technology
Swinburne University of Technology 9

10. Access Control Matrix (II)
4/6/2017
Access Control Matrix (II)
Access Control Matrix or Access Matrix (AM)
the first basic model of access control is the AM
a formal security model in computer systems
characterizes the rights of the subjects with respect to the objects
describes the relationships between subjects and objects in a system
<Lampson, Butler W. (1971), Protection, Proceedings of the 5th Princeton Conference on Information Sciences and Systems>
Swinburne University of Technology
Swinburne University of Technology 10

11. Access Control Matrix (III)
4/6/2017
Access Control Matrix (III)
Access Control Matrix: It has three components
a set of Objects O, a set of Subjects S, and an Access function A
an Object is an entity in the system which has to be protected
a Subject is an entity that has access to the Object
which Subjects can access which Objects is determined by the Access function
Swinburne University of Technology
Swinburne University of Technology 11

12. Access Control Matrix (IV)
4/6/2017
Access Control Matrix (IV)
Access Control Matrix
the rows of the Access function are labelled with the Subject names and its columns by the Object names.
element Ai,j specifies the access which Subject i has to Object j
each element or cell of the matrix consists of a set of strings called access attributes, such as read and write, which are typical access attributes
Swinburne University of Technology
Swinburne University of Technology 12

13. Access Control Matrix (V)
4/6/2017
Access Control Matrix (V)
AM Implementations
operating systems
database systems
Swinburne University of Technology
Swinburne University of Technology 13

14. Access Control Matrix (VI)
4/6/2017
Access Control Matrix (VI)
AM Implementations
a rectangular array of cells, with one row per subject and one column per object
Table: A rectangular array
file1
file2
user1
read, write
read, write, execute
user2
read
execute
user3
write
Swinburne University of Technology
Swinburne University of Technology 14

15. Access Control List (I)
4/6/2017
Access Control List (I)
Access control list (ACL)
each column in an Access Control Matrix (AM) is translated to an Access Control List (ACL)
the ACL contains entries for each subject defining the operations that the subject can execute on the given object
Swinburne University of Technology
Swinburne University of Technology 15

16. Access Control List (II)
4/6/2017
Access Control List (II)
Access control list (ACL): it specifies
which users or system processes are granted access to objects
what operations are allowed on given objects
<Access Control List: Google patents,
Swinburne University of Technology
Swinburne University of Technology 16

17. Access Control List (III)
4/6/2017
Access Control List (III)
ACL Implementations
File System ACL: A file system ACL is
a data structure (table) containing entries that specify individual user or group rights to specific system resources.
resources - programs, files, etc.
entries – access control entries (ACEs).
Swinburne University of Technology
Swinburne University of Technology 17

18. Access Control List (IV)
4/6/2017
Access Control List (IV)
ACL Implementations
File System ACL - used to administrate file permissions
for example, a file has an ACL that contains (Bob, delete)
this gives Bob permission to delete the file.
<MS Windows, Unix/Linux Operating Systems>
Swinburne University of Technology
Swinburne University of Technology 18

19. Access Control List (V)
4/6/2017
Access Control List (V)
ACL Implementations
File System ACL – access ACL and default ACL (Red Hat Linux)
an access ACL is the access control list for a specific file or directory.
a default ACL can only be associated with a directory; if a file within the directory does not have an access ACL.
default ACL uses the rules of the default ACL for the directory.
ACLs can be configured per user or per group.
<
Swinburne University of Technology
Swinburne University of Technology 19

20. Access Control List (VI)
4/6/2017
Access Control List (VI)
ACL Implementations
File System ACL – access ACL and default ACL (Red Hat Linux)
the setfacl utility sets ACLs for files and directories.
# setfacl -m rules files
use the -m option to add/modify the ACL of a file/directory
rule formats u:uid:perms, g:gid:perms
# setfacl -m u:bob:rw /cos80011/waa
<
Swinburne University of Technology
Swinburne University of Technology 20

21. Access Control List (VII)
4/6/2017
Access Control List (VII)
ACL Implementations
SQL-based systems
relational database systems
networking ACLs
Swinburne University of Technology
Swinburne University of Technology 21

22. AM and ACL (VIII) Advantages Disadvantages
4/6/2017
AM and ACL (VIII)
Advantages
easy to implement, simplicity and flexibility are the keys
effective in closed and relatively unchangeable systems
Disadvantages
do not allow modelling the global policy rules by which permissions can change in any particular system
they do not have adequate functionalities to maintain the users and objects in the large-scale systems, where more than one user need same object
Swinburne University of Technology
Swinburne University of Technology 22

23. Outline What is Access Control?
4/6/2017
Outline
What is Access Control?
Access Control Matrix and Access Control List
Role-Based Access Control
User-Role Assignment
Role-Permission Assignment
Attribute-Based Access Control
Context-Aware Access Control
Context-Aware User-Role Assignment
Context-Aware Role-Permission Assignment
Swinburne University of Technology
Swinburne University of Technology 23

24. Role-Based Access Control (I)
4/6/2017
Role-Based Access Control (I)
Role-Based Access Control (RBAC)
a well accepted access control model based on the role of the user is Role-based Access Control (RBAC) was introduced to tackle the problems: global policy rules, large-scale systems
first RBAC, Ferraiolo et al (RBAC92)
the RBAC92 model has been subsequently extended by Sandhu et al (RBAC96)
<Sandhu et al (RBAC96):
<Ferraiolo et al (RBAC92):
Swinburne University of Technology
Swinburne University of Technology 24

25. Role-Based Access Control (II)
4/6/2017
Role-Based Access Control (II)
Role-Based Access Control (RBAC)
in RBAC, it is not important to identify the individual who makes the access request, but to know his position in the structure of an organization
this concept is known as a role in RBAC
the authorizations are not assigned directly to a particular user, but to the user’s role
Swinburne University of Technology
Swinburne University of Technology 25

26. Role-Based Access Control (III)
4/6/2017
Role-Based Access Control (III)
Role-Based Access Control (RBAC)
user group and user role – roles are closely related to the concept of user groups in access control
however, a role brings together a set of users on one side and a set of permissions on the other
whereas user groups are typically defined as a set of users only
Swinburne University of Technology
Swinburne University of Technology 26

27. Role-Based Access Control (IV)
4/6/2017
Role-Based Access Control (IV)
Role-Based Access Control (RBAC): three main concepts
RBAC ensures that only an authorized user is given access to a certain resource, and is based on a user’s role in an organization
users, roles, and permissions in a simple/basic RBAC model
users – subjects are typically represented by users, who are assigned to roles and are granted membership into the roles based on their credentials and responsibilities in an organization
roles – roles represent a job function, describing the authority and responsibility conferred on a user assigned to that role, within an organization
permissions – permissions are assigned to roles, permissions contain resources and operations (the operations are allowed on the objects/resources)
Swinburne University of Technology
Swinburne University of Technology 27

28. Role-Based Access Control (V)
4/6/2017
Role-Based Access Control (V)
Role-Based Access Control (RBAC) Model
User
Assignment UA
Permission
Assignment PA P
Permi-ssion U
User R
Role
Figure: Basic RBAC Model
Swinburne University of Technology
Swinburne University of Technology 28

29. Role-Based Access Control (VI)
4/6/2017
Role-Based Access Control (VI)
Role-Based Access Control (RBAC) Model
U, R and P are the users, roles and permissions respectively
UA is a many-to-many user to role assignment relation
PA is a many-to-many permission to role assignment relation
U𝑨 ⊆𝑼×𝑹
P𝑨 ⊆𝑷×𝑹
Swinburne University of Technology
Swinburne University of Technology 29

30. Role-Based Access Control (VII)
4/6/2017
Role-Based Access Control (VII)
Role-Based Access Control (RBAC): ESP Submissions (Assignments)
user-role and role-permission assignments (policies)
Table: Relationships among users, roles and permissions
User
Role
Permission
<s , ******>
Student
<Assignment2, submit>
<akayes, ******>
Tutor/Marker
<Assignment2, marking>
<acolman, ******>
Lecturer/Convenor
<Assignment2, marks release>
Swinburne University of Technology
Swinburne University of Technology 30

31. Role-Based Access Control (VIII)
4/6/2017
Role-Based Access Control (VIII)
Role-Based Access Control (RBAC): Role Hierarchy
also called role inheritance
for structuring roles to reflect an organization’s lines of authority and responsibility
the senior roles can inherit all permissions from the junior roles
the senior roles can have permissions in addition to those inherited from the junior roles
Swinburne University of Technology
Swinburne University of Technology 31

32. Role-Based Access Control (IX)
4/6/2017
Role-Based Access Control (IX)
Role-Based Access Control (RBAC): Role Hierarchy Example
The lecturer role (senior role) can inherits all permissions from the staff role (junior role)
The lecturer role can have own permissions also
University
User
Student
Staff
UGS
PGS
Tutor
Lecturer
Figure: Role Hierarchy
Swinburne University of Technology
Swinburne University of Technology 32

33. Role-Based Access Control (X)
4/6/2017
Role-Based Access Control (X)
Role-Based Access Control (RBAC): Other RBAC Concepts
RBAC Session (users can create and terminate sessions, to activate/deactivate roles)
RBAC Constraints (predicates that can apply to the UA and PA relations)
<Sandhu et al (RBAC96):
Swinburne University of Technology
Swinburne University of Technology 33

34. Role-Based Access Control (XI)
4/6/2017
Role-Based Access Control (XI)
Role-Based Access Control (RBAC): Patient Medical Records Management
user-role assignments
User
userID
Jane
Jane00X
Mary
Mary00X
Bob
Bob00X
Role
roleID
Registered Nurse
RN00X
Primary-care Physician
PP00X
Emergency Doctor
ED00X
Specialist Physician
SP00X
Physician
P00X
User-Role Assignments (UA)
<Jane00X, PP00X>
<Jane00X, ED00X>
<Mary00X, PP00X>
<Bob00X, RN00X>
<Jane00X, SP00X>
Swinburne University of Technology
Swinburne University of Technology 34

35. Role-Based Access Control (XII)
4/6/2017
Role-Based Access Control (XII)
Role-Based Access Control (RBAC): Patient Medical Records Management
role-permission assignments
Role -Permission Assignments (PA)
<ED00X, <EHR, write>>
<RN00X, <DMR, read>>
<P00X, <DMR, write>>
<P00X, <PMH, write>>
<SP00X, <EHR, read>>
Permission <resource, operation>
<Electronic Health Records (EHR), write>
<daily medical records (DMR), read>
<Past Medical History (PMH), write>
Swinburne University of Technology
Swinburne University of Technology 35

36. Role-Based Access Control (XIII)
4/6/2017
Role-Based Access Control (XIII)
Role-Based Access Control (RBAC): Patient Medical Records Management
The specialist physician role (senior role) can inherits all permissions from the physician role (junior role)
Healthcare
User
Nurse
Physician
Specialist Physician
Registered Nurse
Nurse Manager
Emergency Doctor
Primary-care Physician
Figure: An Excerpt of Healthcare Role Hierarchy
Swinburne University of Technology
Swinburne University of Technology 36

37. Role-Based Access Control (XIV)
4/6/2017
Role-Based Access Control (XIV)
Role-Based Access Control (RBAC): Patient Medical Records Management UA
<Jane00X, PP00X>
<Jane00X, ED00X>
<Mary00X, PP00X>
<Bob00X, RN00X>
<Jane00X, SP00X> PA
<ED00X, <EHR, write>>
<RN00X, <DMR, read>>
<P00X, <DMR, write>>
<P00X, <PMH, write>>
<SP00X, <EHR, read>>
Role
roleID
Registered Nurse
RN00X
Primary-care Physician
PP00X
Emergency Doctor
ED00X
Specialist Physician
SP00X
Physician
P00X
Physician
Emergency Doctor
Primary-care Physician
Specialist Physician
Swinburne University of Technology
Swinburne University of Technology 37

38. Role-Based Access Control (XV)
4/6/2017
Role-Based Access Control (XV)
Role-Based Access Control (RBAC): main part
Organization
Resource
Role
Operation
Swinburne University of Technology
Swinburne University of Technology 38

39. Role-Based Access Control (XVI)
4/6/2017
Role-Based Access Control (XVI)
Advantages
simplifies management of permissions
effective/useful model in large-scale systems/domains
Disadvantages
the user-role and role-permission assignments are static without taking into account the dynamic attributes, such as the location of users
this makes a less effective solution in today’s open and dynamic environments
Swinburne University of Technology
Swinburne University of Technology 39

40. Outline What is Access Control?
4/6/2017
Outline
What is Access Control?
Access Control Matrix and Access Control List
Role-Based Access Control
User-Role Assignment
Role-Permission Assignment
Attribute-Based Access Control
Context-Aware Access Control
Context-Aware User-Role Assignment
Context-Aware Role-Permission Assignment
Swinburne University of Technology
Swinburne University of Technology 40

41. Attribute-Based Access Control (I)
4/6/2017
Attribute-Based Access Control (I)
Attribute-Based Access Control (ABAC)
a new access control paradigm where access rights are granted to users through the use of policies which combine attributes together
the policies can use any type of attributes (user attributes, resource attribute, etc.)
it is a rule-based approach to access control, it does not use the concept of a role
the building blocks in the ABAC model are the attributes
an ABAC policy specifies which constraints need to be satisfied based on the attributes (e.g., user age is greater than 20) in order to grant access to an object
Swinburne University of Technology
Swinburne University of Technology 41

42. Attribute-Based Access Control (II)
4/6/2017
Attribute-Based Access Control (II)
Attribute-Based Access Control (ABAC)
the formal definition of basic ABAC is composed of four parts: access control related entities, attributes of entities, policy representation, and policy evaluation
entities – requestor (Req), resource (Res), action (Act), environment (Env)
attributes of entities (e.g., attributes of environment (Attr(Env)) – the current date or time)
policy specification – the definition of access control policies
policy evaluation – the process of making an access decision based on the security policy
<ABAC,
Swinburne University of Technology
Swinburne University of Technology 42

43. Attribute-Based Access Control (III)
4/6/2017
Attribute-Based Access Control (III)
Attribute-Based Access Control (ABAC): policy evaluation
an access control decision is made by the evaluation function ( 𝑃 𝑖_𝑎𝑑𝑓() ), access control decision function, ADF
it takes the attributes of the requestor, the resource, the action, the environment as parameters
𝑷 𝒊_𝒂𝒅𝒇() 𝐴𝑡𝑡𝑟 𝑅𝑒𝑞 ,𝐴𝑡𝑡𝑟 𝑅𝑒𝑠 ,𝐴𝑡𝑡𝑟 𝐴𝑐𝑡 ,𝐴𝑡𝑡𝑟 𝐸𝑛𝑣
=𝒑𝒆𝒓𝒎𝒊𝒕 𝑜𝑟 𝒅𝒆𝒏𝒚
Swinburne University of Technology
Swinburne University of Technology 43

44. Attribute-Based Access Control (IV)
4/6/2017
Attribute-Based Access Control (IV)
eXtensible Access Control Markup Language (XACML)
is the standard that implements attribute-based access control
a standard XML-based protocol for access control policies
suitable for a variety of application environments (e.g., Web-based)
uses the attributes of subject, resource, action, and environment
this framework contains PEP, PDP, PIP, and PAP
<OASIS XACML 3.0 (2013),
Swinburne University of Technology
Swinburne University of Technology 44

45. Attribute-Based Access Control (V)
4/6/2017
Attribute-Based Access Control (V)
eXtensible Access Control Markup Language (XACML): four main components
Policy Enforcement Point (PEP)
Policy Decision Point (PDP)
Policy Administration Point (PAP)
Policy Information Point (PIP)
<OASIS XACML 3.0 (2013),
Swinburne University of Technology
Swinburne University of Technology 45

46. Attribute-Based Access Control (VI)
4/6/2017
Attribute-Based Access Control (VI)
XACML Data Authorization Framework
<OASIS XACML 3.0 (2013),
Figure: XACML Data Flow Diagram
Swinburne University of Technology
Swinburne University of Technology 46

47. Attribute-Based Access Control (VII)
4/6/2017
Attribute-Based Access Control (VII)
XACML Data Authorization Framework: when access request comes from the access requesters (users)
the PEP intercepts the access requests from users and sends the requests to the PDP (through the context handler)
the PDP makes access decisions according to the security policy (policy set) written by the PAP
the PDP uses the attributes of the subjects, the resources, and the environment obtained by querying the PIP (via the context handler)
the access decision given by the PDP is sent to the PEP(through the context handler)
the PEP sends either permitted or denied request to the users according to the decision of PDP
Swinburne University of Technology
Swinburne University of Technology 47

48. Attribute-Based Access Control (VIII)
4/6/2017
Attribute-Based Access Control (VIII)
XACML Implementation
Domain-specific Inputs (from the requesters)
converted to
XACML Request Context (.xml)
XACML Policy (.xml)
XACML Response Context (.xml)
Domain-specific Outputs (back to the requesters)
Swinburne University of Technology
Swinburne University of Technology 48

49. Attribute-Based Access Control (IX)
4/6/2017
Attribute-Based Access Control (IX)
Language Model of XACML
Figure: XACML Context and Policy
<OASIS XACML 3.0 (2013),
Swinburne University of Technology
Swinburne University of Technology 49

50. Attribute-Based Access Control (X)
4/6/2017
Attribute-Based Access Control (X)
Advantages
easy to implement/setup
very useful model in small-scale systems/domains
Disadvantages
when the number of users is high, the number of authorizations can become extremely large, which complicates the administration tasks
this brings high complexity of security administration and significant cost of management of growing large-scale systems
it does not provide adequate functionalities for dynamic access permissions
Swinburne University of Technology
Swinburne University of Technology 50

51. Outline What is Access Control?
4/6/2017
Outline
What is Access Control?
Access Control Matrix and Access Control List
Role-Based Access Control
User-Role Assignment
Role-Permission Assignment
Attribute-Based Access Control
Context-Aware Access Control
Context-Aware User-Role Assignment
Context-Aware Role-Permission Assignment
Swinburne University of Technology
Swinburne University of Technology 51

52. Context-Aware Access Control (I)
4/6/2017
Context-Aware Access Control (I)
Static Access Permissions AM
ACL
RBAC
ABAC
XACML
Dynamic access permissions (to dynamically make access control decisions)
The dynamic user-role and role-permission assignments
Access to medical records of patients should be dynamically controlled depending on the location and request time of users. Normally, a nurse that is not located in the hospital should not have access to medical records of patients. Moreover, this access is allowed only during her ward duty time, and knowing the relationship between patient and nurse.
Swinburne University of Technology
Swinburne University of Technology 52

53. Context-Aware Access Control (II)
4/6/2017
Context-Aware Access Control (II)
RBAC has become the most widely used access control model
The CAAC model adopts RBAC concepts and extends its user-role and role-permission assignments
CAAC incorporates the dynamic attributes (context information) into both user-role and role-permission assignments
Swinburne University of Technology
Swinburne University of Technology 53

54. Context-Aware Access Control (III)
4/6/2017
Context-Aware Access Control (III)
CAAC Policy Framework
<A. S. M. Kayes, Jun Han, and Alan Colman, A Semantic Policy Framework for Context-Aware Access Control Applications, TrustCom 2013,
Swinburne University of Technology
Swinburne University of Technology 54

55. Context-Aware Access Control (IV)
4/6/2017
Context-Aware Access Control (IV)
Dynamic Context-Aware Environments
Shift from desktop environments to dynamic environments described by Mark Weiser, where users need seamless access to various resources at anytime from anywhere even when they are on the move
Pervasive/Ubiquitous environments
Privacy and security of accessing resources/services is of greater concern
Context information
<Mark Weiser, Some computer science issues in ubiquitous computing, Comm. ACM 1993,
Swinburne University of Technology
Swinburne University of Technology 55

56. Context-Aware Access Control (V)
4/6/2017
Context-Aware Access Control (V)
Context Information and Context Awareness
Dey, Context information is defined as any information that can be used to characterize the situation of an entity and Context awareness is the ability to use context information to provide relevant information and/or services to the user
Our focus is “CAAC Model”
Context-aware access control (CAAC), decision making based on the context information, reauthorization of access if context changes
<Dey et al, A Conceptual Framework for Context-Aware Applications, PUC 2001,
Swinburne University of Technology
Swinburne University of Technology 56

57. Context-Aware Access Control (VI)
4/6/2017
Context-Aware Access Control (VI)
Application Scenario
Users from different locations
Users from
different
devices
A Patient in
an Emergency
Health
Condition
Users at
different times
Organization
Resources
User
Figure: User-to-Resource Access Scenario in Context-Aware Environments
Swinburne University of Technology
Swinburne University of Technology 57

58. Context-Aware Access Control (VII)
4/6/2017
Context-Aware Access Control (VII)
Application Scenario
A patient Bob who is in the emergency room due to a heart attack. While not being Bob's usual treating physician, Jane, a medical practitioner at the hospital, is required to treat Bob and needs to access Bob's electronic health records from the emergency room.
User
Resources
Healthcare
Patients’
Medical
Records
Figure: Healthcare Scenario
Swinburne University of Technology
Swinburne University of Technology 58

59. Context-Aware Access Control (VIII)
4/6/2017
Context-Aware Access Control (VIII)
Application Scenario
After getting emergency treatment, Bob is shifted and has been assigned a registered nurse Mary, who has regular follow-up visits to monitor his health condition. Mary needs to access several types of Bob's records (daily medical records and private health records) from the general ward.
User
Resources
Healthcare
Patients’
Medical
Records
Figure: Healthcare Scenario
Swinburne University of Technology
Swinburne University of Technology 59

60. Context-Aware Access Control (IX)
4/6/2017
Context-Aware Access Control (IX)
Application Scenario
Different users with different roles from different environments for different intentions
Privacy and security
User
Resources
Healthcare
Patients’
Medical
Records
Figure: Healthcare Scenario
Swinburne University of Technology
Swinburne University of Technology 60

61. Context-Aware Access Control (X)
4/6/2017
Context-Aware Access Control (X)
Main Challenges/Requirements
(Req1) - representation of context entities and context information relevant to access control (context model)
(Req2) - inferring high-level context information from the available information (reasoning model)
(Req3) - incorporating dynamic contextual information into access control policies (policy model)
Swinburne University of Technology
Swinburne University of Technology 61

62. Context-Aware Access Control (XI)
4/6/2017
Context-Aware Access Control (XI)
Figure: CAAC Model
Swinburne University of Technology
Swinburne University of Technology 62

63. Context-Aware Access Control (XII)
4/6/2017
Context-Aware Access Control (XII)
CAAC Model Concepts (elements)
Users(U) – a user is a human-being (who is a service requester) interacting with a computing system, whose access request is being controlled (e.g., Jane, Mary)
Roles(R) – a role reflect user's job function within the organization (e.g., healthcare domain)
Resources(Res) – a resource is an object protected by access control that represents the data/information container (e.g., patient’s electronic health records)
Operations(Op) - an operation is an action that can be executed on the resources (e.g., read, write)
Permissions(P) - permissions are the approvals to perform certain operations on resources, by the users who initiate access requests
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64. Context-Aware Access Control (XIII)
4/6/2017
Context-Aware Access Control (XIII)
CAAC Model Concepts (elements)
Context Information(CI) – context Information used in an access control decision is defined as any relevant information about the state of an entity or the state of a relevant relationships between entities (e.g., location of the patient, social or interpersonal relationship between doctor and patient)
Policies(Pol) – two sets of policies: the context-aware user-role assignment policies and context-aware role-permission assignment policies
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Swinburne University of Technology 64

65. Context-Aware Access Control (XIV)
4/6/2017
Context-Aware Access Control (XIV)
Figure: CAAC Model
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Swinburne University of Technology 65

66. Context-Aware Access Control (XV)
4/6/2017
Context-Aware Access Control (XV)
CAAC Model Concepts (relationships)
Role Hierarchy(RH) – it supports the concept of role inheritance (like RBAC). The role is considered in a hierarchical manner in that if a permission assigned to a junior role, then it is also assigned to all the senior roles of that role
Resource Hierarchy(ResH) – the resource is also considered in a hierarchical manner in that if a user has the right to access a resource with the highest granularity level, then he also has the right to access the lower granularity levels of that resource
Operation Assignment(OpA) – each operation could be associated with many resources, and for each resource could be granted to many operations
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Swinburne University of Technology 66

67. Context-Aware Access Control (XVI)
4/6/2017
Context-Aware Access Control (XVI)
CAAC Model Concepts (relationships)
Context-Aware User-Role Assignment(CAURA) – a many-to-many mapping between a set of users and roles, when a set of dynamic contextual conditions are satisfied
Context-Aware Role-Permission Assignment(CARPA) – a many-to-many mapping between a set of roles and permissions, when a set of dynamic contextual conditions are satisfied
CAUR𝑨 ⊆𝑼×𝑹×𝑪𝑰
CARP𝑨 ⊆𝑹×𝑷×𝑪𝑰
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Swinburne University of Technology 67

68. Context-Aware Access Control (XVII)
4/6/2017
Context-Aware Access Control (XVII)
Context Ontology
Policy Ontology
Figure: CAAC Model
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69. Context-Aware Access Control (XVIII)
4/6/2017
Context-Aware Access Control (XVIII)
Advantages
dynamic access permissions (dynamic access control decision making)
dynamic user-role and role-permission assignments
efficient model in today’s dynamic and context-aware environments
Disadvantages
implementation efforts
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70. Review Access Control AM ACL RBAC ABAC XACML CAAC 4/6/2017
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Swinburne University of Technology 70

71. Next Semantic Web Semantic Technology Ontology Concept
4/6/2017
Next
Semantic Web
Semantic Technology
Ontology Concept
OWL, DL and SWRL
Ontology-Based Framework for Access Control
XACML-Based Framework for Access Control
XACML for RBAC
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72. Questions? ABAC, Core XACML – attribute-based RBAC – role-based
4/6/2017
Questions?
ABAC, Core XACML – attribute-based
RBAC – role-based
CAAC – ?
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73. Questions? akayes@swin.edu.au (dblp: A. S. M. Kayes)
4/6/2017
Questions?
ABAC, Core XACML – attribute-based
RBAC – role-based
CAAC – role- and attribute-based
(dblp: A. S. M. Kayes)
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