Chapter8_Security in Computer Networks.ppt

Chapter work Security
A note on the use of these ppt slides:
We’re making these slides freely available to all (faculty, students, readers). They’re in PowerPoint form so you can add, modify, and delete slides (including this one) and slide content to suit your needs. They obviously represent a lot of work on our part. In return for use, we only ask the following:
If you use these slides (., in a class) in substantially unaltered form, that you mention their source (after all, we’d like people to use our book!)
If you post any slides in substantially unaltered form on a , that you note that they are adapted from (or perhaps identical to) our slides, and note our copyright of this material.
Thanks and enjoy! JFK/KWR
All material copyright 1996-2005
Kurose and . Ross, All Rights Reserved
working: A Top Down Approach Featuring the , 3rd edition. Jim Kurose, Keith RossAddison-Wesley, July 2004.
1
8: Network Security
Chapter 8: Network Security
Chapter goals:
understand principles work security:
cryptography and its many uses beyond “confidentiality”
authentication
message integrity
key distribution
security in practice:
firewalls
security in application, transport, network, link layers
2
8: Network Security
Chapter 8 roadmap
What work security?
Principles of cryptography
Authentication
Integrity
Key Distribution and certification
Access control: firewalls
Attacks and counter measures
Security in many layers
3
8: Network Security
What work security?
Confidentiality: only sender, intended receiver should “understand” message contents
sender encrypts message
receiver decrypts message
Authentication: sender, receiver want to confirm identity of each other
Message Integrity: sender, receiver want to ensure message not altered (in transit, or afterwards) without detection
Access and Availability: services must be accessible and available to users
4
8: Network Security
Friends and enemies: Alice, Bob, Trudy