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Lecture Network security: Chapter 21 - Dr. Munam Ali Shah

In this chapter, you will learn: Key distribution mechanism will be discuss in detail, the role of a KDC (key distribution center), key distribution design constraints will be explored. In this chapter students will be able to present an understanding of the confidentiality using symmetric encryption, demonstrate knowledge about the key distribution. | Network Security Lecture 21 Presented by: Dr. Munam Ali Shah Part – 2 (e): Incorporating security in other parts of the network Summary of the Previous Lecture In previous lecture talked about achieving Confidentiality using symmetric encryption We also explored Link vs. end to end encryption Summary of the previous lecture have two major placement alternatives link encryption vulnerable links are equipped with encryption device En/decryption occurs independently on every link requires many devices in a large network User has no control over security of these devices Many keys must be provided end-to-end encryption encryption occurs between original source and final destination need devices at each end with shared keys Authentication Summary of the previous lecture Outlines of today’s lecture Key Distribution mechanism will be discuss in detail The role of a KDC (key distribution center) Key Distribution design constraints will be explored Objectives You would be able to present an . | Network Security Lecture 21 Presented by: Dr. Munam Ali Shah Part – 2 (e): Incorporating security in other parts of the network Summary of the Previous Lecture In previous lecture talked about achieving Confidentiality using symmetric encryption We also explored Link vs. end to end encryption Summary of the previous lecture have two major placement alternatives link encryption vulnerable links are equipped with encryption device En/decryption occurs independently on every link requires many devices in a large network User has no control over security of these devices Many keys must be provided end-to-end encryption encryption occurs between original source and final destination need devices at each end with shared keys Authentication Summary of the previous lecture Outlines of today’s lecture Key Distribution mechanism will be discuss in detail The role of a KDC (key distribution center) Key Distribution design constraints will be explored Objectives You would be able to present an understanding of the confidentiality using symmetric encryption . You would be able demonstrate knowledge about the Key distribution. Key Distribution symmetric schemes require both parties to share a common secret key issue is how to securely distribute this key often secure system failure due to a break in the key distribution scheme Key Distribution Given parties A and B have various key distribution alternatives: A can select key and physically deliver to B third party can select & deliver key to A & B if A & B have communicated previously can use previous key to encrypt a new key if A & B have secure communications with a third party C, C can relay key between A & B 9 Key Storage Master Key & Session Key Master Key/ Encrypting Key: A pre-shared key is used to encrypt a randomly generated and insecurely communicated Working Key (called the "Session" key). The Working Key is then used for encrypting data to be exchanged. This technique still finds widespread use in the financial .