information flow analysis信息安全概论课件06.pptVIP

Copyright ? 2008 by Jingsha He November 25, 2008 Copyright ? 2008 by Jingsha He 1 Introduction to Information Security Prof. Jingsha He School of Software Engineering Beijing University of Technology November 25, 2008 Copyright ? 2008 by Jingsha He 2 Fact of the Lecture Quantum computing is a theoretical way of using the properties of matter at the quantum mechanical (microscopic) level in order to build computational systems. Quantum computers would not work like ordinary computers, but on a whole new principle. It has been theorized that quantum computers could break standard encryption codes in a fraction of a second. The race is on to build quantum computers. November 25, 2008 Copyright ? 2008 by Jingsha He 3 Practices Information Flow Analysis November 25, 2008 Copyright ? 2008 by Jingsha He 4 Identification Authentication Encryption Decryption Access Control CEO Identification Authentication Encryption Decryption Regular Employee Information Flow Auditing November 25, 2008 Copyright ? 2008 by Jingsha He 5 Information Flow Policy Any confidentiality and integrity model embodies an information flow policy There is thus the need for assurance that information flow doesnt violate the constraints of such a policy Access control can constrain the rights of a user, but not the flow of information between subjects or objects There is thus the need for mechanisms that control the flow of information in addition to access control Example In the Bell-LaPadula model, information can flow from one object to another if and only if the second object dominates the first November 25, 2008 Copyright ? 2008 by Jingsha He 6 Definition of Information Flow Components Object x Object y Sequence of commands S Definition Information flows from object x to object y if, after the execution of the sequence of commands S, the value in object y allows one to deduce the value in object x Notation y ← x x is called the source of the information flow y is called the target of the informat