Computer Networking-ch7-review-NetworkSecurity.pdf

C r e a t e Chapter 7: Network security d b y N e e v Foundations: i a D o c what is security? u m e n cryptography t C o n authentication v e r t e message integrity r t r i a l key distribution and certification v e r s i o Security in practice: n h t t p application layer: secure e-mail : / / w w w transport layer: Internet commerce, SSL, SET . n e e network layer: IP security v i a . c o m Shaowen Yao, School Of Software, YNU 1 C r e a t e Friends and enemies: Alice, Bob, Trudy d b y N e e v i a D o c u m e n t C o n Figure 7.1 goes here v e r t e r t r i a l v e r s i o n h t t p well-known in network security world : / / w w Bob, Alice (lovers!) want to communicate “securely” w . n e Trudy, the “intruder” may intercept, delete, add e v i a messages . c o m Shaowen Yao, School Of Software, YNU 2 C r e a t e What is network security? d b y N e e v i a D Secrecy: only sender, intended receiver should o c u m “understand” msg contents e n t C sender encrypts msg o n v e receiver decrypts msg r t e r t r i Authentication: sender, receiver want to a l v e r confirm identity of each other s i o n h t Message Integrity: sender, receiver want to t p : / / w ensure message not altered (in transit, or w w . n afterwards) without detection e e v i a . c o m