Outline for October 7, 2022

Reading: text, §10.4–10.5, 11.1–11.2, 12.1
Due: Homework 1, due October 5; Project selection, due Oct 7

1. Cryptographic Checksums
   1. Function y = h(x): easy to compute y given x; computationally infeasible to compute x given y
   2. Variant: given x and y, computationally infeasible to find a second x′ such that y = h(x′)
   3. Keyed vs. keyless

2. Digital Signatures
   1. Judge can confirm, to the limits of technology, that claimed signer did sign message
   2. RSA digital signatures: sign, then encipher, then sign
   3. El Gamal digital signatures

3. Session and interchange keys

4. Key Exchange
   1. Needham-Schroeder and Kerberos
   2. Public key; man-in-the-middle attacks
   3. The discrete log problem and Diffie-Hellman

5. Attacks
   1. Precomputation
   2. Misordered blocks
   3. Statistical regularities
   4. Type flaw

Matt Bishop Office: 2209 Watershed Sciences Phone: +1 (530) 752-8060 Email: mabishop@ucdavis.edu

ECS 235A, Computer and Information Security Version of October 5, 2022 at 7:52PM

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