Outline for October 23, 2023

Reading: text, §13, 15.1–15.5
Due: Homework 2, due October 23; Background Research, due October 27

1. 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

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

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

5. Multi-factor authentication

6. Identity
   1. Files, objects
   2. Users, groups, roles

7. Certificates
   1. X.509v4 Distinguished Names
   2. Registration and certification authorities

Matt Bishop Office: 2209 Watershed Sciences Phone: +1 (530) 752-8060 Email: [email protected]

ECS 235A, Computer and Information Security Version of October 23, 2023 at 2:26PM

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