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Mạng và viễn thông P39

Network Security Measures Improvements in,andexpansionsof,communicationssystemsandnetworkshaveleftmany companies open to breaches in confidentiality, industrial espionage and abuse. Sometimes such breaches go unnoticed for longperiods,andcanhaveseriousbusiness or costimplications. Equally damaging can the impactof simple mistakes, misinterpreted, or distorted information. be Increased belief in the reliability of systems and the accuracy of information has brought great gains in efficiency,but blind belief suppresses the questions which might have confirmed the need for corrections. . | Networks and Telecommunications Design and Operation Second Edition. Martin P. Clark Copyright 1991 1997 John Wiley Sons Ltd ISBNs 0-471-97346-7 Hardback 0-470-84158-3 Electronic 39 Network Security Measures Improvements in and expansions of communications systems and networks have left many companies open to breaches in confidentiality industrial espionage and abuse. Sometimes such breaches go unnoticed for long periods and can have serious business or cost implications. Equally damaging can be the impact of simple mistakes misinterpreted or distorted information. Increased belief in the reliability of systems and the accuracy of information has brought great gains in efficiency but blind belief suppresses the questions which might have confirmed the need for corrections. This chapter describes the various levels of information protection which may be provided by different types of telecommunications networks and the corresponding risks. It goes on to make practical suggestions about how a company s protection needs could be assessed and how different types of information can best be secured in transit 39.1 THE TRADE-OFF BETWEEN CONFIDENTIALITY AND INTERCONNECTIVITY The man who sold the first telephone must have been a brilliant salesman for there was no-one for the first customer to talk to On the other hand what confidence the customer could have had that there were no eavesdroppers on his conversations The simplicity of the message should be a warning to all the more people on your network the greater your risk. As the number of connections on a network increases users are subjected to the risk of interception tapping or eavesdropping greater uncertainty about who they are communicating with have you reached the right telephone or not which caller might be masquerading as someone else the risk of time-wasting mistakes an incorrect access to a database or a misinterpretation of data may lead to the corruption or deletion of substantial amounts of data 711 712 .