Outline for October 14, 2022

Reading: text, §13.5–13.8, 15.1–15.5
Due: Homework 2, due October 21; Progress report, due Nov 4

1. Defenses
   1. For trial and error at login: dropping or back-off
   2. For thwarting dictionary attacks: salting

2. One-Time Password
   1. Password is valid for only one use
   2. May work from list, or new password may be generated from old by a function or a hardware token

3. Challenge-response systems
   1. Computer issues challenge, user presents response to verify secret information known/item possessed
   2. Example operations: f(x) = x+1, random, string (for users without computers), time of day, computer sends E(x), you answer E(D(E(x))+1)
   3. Note: password never sent over network

4. Biometrics
   1. Depend on physical characteristics
   2. Examples: pattern of typing (remarkably effective), retinal scans, etc.

5. Location
   1. Bind user to some location detection device (human, GPS)
   2. Authenticate by location of the device

6. Multi-factor authentication

7. Identity
   1. Files, objects
   2. Useers, groups, roles

8. Certificates

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

ECS 235A, Computer and Information Security Version of October 13, 2022 at 10:14PM

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