Lecture 23

Fall 2011, Siena College

Lecture 23: Encryption and Secure HTTP
Date: Friday, December 2, 2011

Agenda

Announcements
Meet in lab as usual on Monday for an in-lab task that I hope everyone will finish before leaving
Design project progress reports now due
About the final exam
- scheduled for Thursday, December 15, 11-1, RB 302
- material is cumulative but exam will focus on topics since exam 2
- same ground rules as other exams: closed book/notes but reference sheets will be provided
About course evaluations
Lecture assignment 22 recap
Encryption
- basics
- public-key encryption
- digital signatures

Due at the start of class, Wednesday, December 7.

Please submit answers to these questions either as a hard copy (typeset or handwritten are OK) or by email to jteresco AT siena.edu by the start of class. Please use a clear subject line when submitting by email (e.g., CS 180 Lecture Assignment 23, Joe Student). We will discuss these questions at the start of class, so no late submissions are accepted.

We saw in class how http web connections are made in clear text (the data transmitted may be seen by others) while https connections are encrypted. Name two reasons why all web traffic doesn't use https. (4 points)
Explain how a certificate from a trusted authority would prevent the man in the middle attack described in class involving the message from Alice to Dilbert that was intercepted by Catbert. (6 points)

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