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25 lines
678 B
Markdown
25 lines
678 B
Markdown
# CSE4303 Introduction to Computer Security (Lecture 12)
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## Asymmetric Encryption
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### Motivation
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#### Symmetric key exchange: TTPs
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Idea: Trusted Third Party (TTP) is always-available key manager
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- Assume secure channel exists between every user and TTP
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- KA = shared key between user A and TTP
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- Generates/distributes keys to user pairs on demand
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- KAB = shared key between user A and user B
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Symmetric-key encryption: challenges
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1. Key storage: one per user pair, $O(n^2)$ total for $n$ users
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2. Key exchange: how to do it over non-secure channel?
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### Key Exchange
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[Diffie-Hellman](https://notenextra.trance-0.com/CSE442T/CSE442T_L16/#diffie-helmann-key-exchange)
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