Topics in Cryptography

Session 01: A bird's view of the journey.

Transcript

1. Special Topics in Cryptography Mohammad Mahmoody
2. Cryptography’s main goals
3. Secure communication
4. Historic Ciphers
5. Privacy / confidentiality
6. Integrity / Authentication
7. Integrity / Authentication
8. Not loosing in chess to the grand master
9. Tool: Pseudorandom (number) generators
10. Public Key Encryption Revolution (70’s)
11. Four main problems in cryptographic
12. Main tool for public-key cryptography: Number theory and structured mathematics
13. Beyond Encryption and Authentication
14. Multi-party Computation
15. Yao’s Billionaires Problem
16. Poker over the phone
17. Generalization: multi-party computation
18. Multiparty consensus mechanisms (and block-chain protocols …)
19. Weird useful tool: Zero Knowledge Proofs
20. More powerful forms of Encryption
21. Homomorphic Encryption
22. Searchable Encryption
23. And many more…
25. Encryption : Perfect secrecy and its limitations
27. Chapters 1-2 of Katz-Lindell book • Steganography and why it is not a good idea • Defining Perfect Secrecy • Problems with perfect secrecy
28. Setting for private-key encryption schemes • Alice and Bob share some “secret information” in advance • They want to communicate a new message secretly. • The communication happens in public.
29. Steganography • Art of concealing the message in “innocent-looking” messages.
30. Steganography • Even the algorithm used by Alice and Bob is hidden… • When is it useful? • What is wrong with it?
31. Kerckhoffs's principle
32. Caesar cipher (weak variant) • the th letter is substituted with ( + ) th letter. • Is it secure?
33. Caesar Cipher (strong variant) • Secret key: a random permutation over all letters. • Key size: log 26! > 88 bits • Is it now secure?