280 likes | 357 Views
____________________________. XML Access Control for Semantically Related XML Documents & A Role-Based Approach to Access Control For XML Databases BY Asheesh Kumar AXK0656 April 27, 2006.
E N D
____________________________ XML Access Control for Semantically Related XML Documents & A Role-Based Approach to Access Control For XML Databases BY Asheesh Kumar AXK0656 April 27, 2006
XML Access Control for Semantically Related XML Documents_____________________________________________ • Vijay Parmar and Hongchi Shi Department of Computer Science & Computer Engineering University of Missouri- Columbia, USA • Su-Shing Chen Dept of computer & Information Science & Engineering University of Florida, USA
A Role-Based Approach to Access Control for XML Databases_____________________________________________ • Zingzhu Wang Department of Computer Science University of Western Ontario, Canada • Su-Shing Chen Department of Computer Science University of Western Ontario, Canada
XML Access Control for Semantically Related XML Documents _____________________________________________ • XML most preferred way to store & exchange information • Need to provide controlled access to such information is imminent • Authors propose an access control policy & mechanism for a collection of semantically related XML documents
XML Access Control for Semantically Related XML Documents _____________________________________________ Features of proposed access control mechanism • It is developed for XML documents- semantically related • Access control conditions can be specified based on contents of the document • Access control is role based
XML Access Control for Semantically Related XML Documents _____________________________________________ • Assume that each XML document resembles an entity playing a certain role • Each entity has certain relationships with other entities (XML document) • An access request may result in data coming from more than one document in the collection • Semantic relationships, so document playing a certain role can have access to other entities playing a different role
XML Access Control for Semantically Related XML Documents _____________________________________________ • Sample relationships of entities playing particular role
XML Access Control for Semantically Related XML Documents _____________________________________________ • Relationship between entities (XML documents)
XML Access Control for Semantically Related XML Documents _____________________________________________ Observations for Access Control Policy • XML documents are not accessed by the document names.. • Entity playing a role may requests data from collection of XML documents by giving a general request over the whole collection • Now, requesting entities identification & role would cause access control mechanism to restrict its access according to access control policy • All documents in collection must comply with same DTD, so all entities playing a similar role have same structure but different content
XML Access Control for Semantically Related XML Documents _____________________________________________ Overview of Access Control Policy Specification The Access Control Policy DTD
XML Access Control for Semantically Related XML Documents _____________________________________________ Operation types and execution • Read • Write • Create • Delete Operations are performed by first querying the XML document collection with the XPATH query expression provided in the access request
XML Access Control for Semantically Related XML Documents _____________________________________________ Steps involved in Read Operation • XPath query is processed on collection of XML documents • Results checked for list of allowed elements for read operation under the appropriate role • Result of above step leaves a set of document fragment that is further checked for access control condition • Condition for each allowed element and sub element is checked • If conditions are satisfied, the content of allowed element are not deleted
XML Access Control for Semantically Related XML Documents _____________________________________________ • A sample Read operation
XML Access Control for Semantically Related XML Documents _____________________________________________
XML Access Control for Semantically Related XML Documents _____________________________________________ Condition Specification • Conditions indicate constraint for the access to the particular allowed element for a specific operation • Presence of name of an element in the allowed element list indicates that it is allowed for access for a particular role only if the conditions are satisfied • Conditions can be specified in the access control policy document with the ‘condition’ element • AND & OR conditions ..
XML Access Control for Semantically Related XML Documents _____________________________________________
XML Access Control for Semantically Related XML Documents _____________________________________________ Condition types • Prohibit • Equals • Exists • NotExists
XML Access Control for Semantically Related XML Documents _____________________________________________ A sample Condition Specification
XML Access Control for Semantically Related XML Documents _____________________________________________ A student is not allowed to update his grades but allowed to view them
XML Access Control for Semantically Related XML Documents _____________________________________________ Overall Access control model
A Role-Based Approach to Access Control for XML Databases _____________________________________________ • Propose to combine Role Graph Model, Authorization Type Graph and Authorization Object Schema, Authorization Object Graph • Group of permission -> Role -> assigned to users • Permissions are privileges • Privileges are made up of object and access mode ( read/ write etc) • Object part of an XML database is any part of XML
A Role-Based Approach to Access Control for XML Databases _____________________________________________ • Example Role Graph
A Role-Based Approach to Access Control for XML Databases _____________________________________________ • Authorization Object Schema for example
A Role-Based Approach to Access Control for XML Databases _____________________________________________ • Authorization Object Graph for example
A Role-Based Approach to Access Control for XML Databases _____________________________________________ • Authorization Type Graph
A Role-Based Approach to Access Control for XML Databases _____________________________________________ • Authorization Association Matrix
Thank You Asheesh Kumar AXK0656