A Model For Network Security
                                     Objectives of the 
                                     Topic 
                                     • After completing this 
                                       topic, a student will 
                                       be able to
                                        –describe a model 
                                          for network 
                                          security.
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             A Model For Network Security
                                     Figures and material 
                                     in this topic have 
                                     been
                                     • adapted from 
                                       “Network Security 
                                       Essentials: 
                                       Applications and 
                                       Standards”, 2014, by 
                                       William Stallings.
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              A Model For Network Security
                                     • Assume a message is 
                                        to be transferred from 
                                        one party to another 
                                        across some sort of 
                                        Internet service. 
                                     • The two parties, who 
                                        are the principals  in 
                                        this transaction, must 
                                        cooperate for the 
                                        exchange to take 
                                        place. 
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             A Model For Network Security
                                     • A logical information 
                                       channel is established 
                                       by defining a route 
                                       through the Internet 
                                       from source to 
                                       destination and by the 
                                       cooperative use of 
                                       communication 
                                       protocols (e.g., 
                                       TCP/IP) by the two 
                                       principals.
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              A Model For Network Security
                                     • To protect the 
                                        information from an 
                                        opponent who may 
                                        present a threat to 
                                        confidentiality, 
                                        authenticity, and so 
                                        on, security comes 
                                        into play.
                                     • All of the security 
                                        techniques have two 
                                        components:
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