Manifest: Wednesday 30 August 2000

Assignments Due
Thursday, 31 August (noon)	Registration Survey
Monday, 11 September	Problem Set 1

Mailing Lists
It is highly recommended that everyone in the class subscribe to these mailing lists:

• RISKS - can be read as web, or send a message to risks-request@csl.sri.com with subject SUBSCRIBE.
• Crypto-gram Newsletter (monthly); to subscribe send a blank message to crypto-gram-subscribe@chaparraltree.com.

Readings

Read before 4 September (handed out today):

• Richard Feynman. Safecracker Meets Safecracker. From "Surely You're Joking, Mr. Feynman!: Adventures of a Curious Character", Richard P. Feynman (Ralph Leighton), Norton 1985.
• Stallings, Chapter 1 and 2.

Cryptogram

XBW HGQW XS ACFPSUWG FWPGWXF CF AWWKZV CDQGJCDWA CD BHYJD DJXHGW; WUWD XBW ZWJFX PHGCSHF YCDA CF GSHFWA LV XBW KGSYCFW SI FBJGCDQ RDSOZWAQW OCXBBWZA IGSY SXBWGF.

Questions

• Why is computer security important?
• Terms: cryptology, cryptography, cryptanalysis, steganography, encryption, decryption, plaintext, ciphertext
• What is the reasoning behind Kerchoff's principle?
• What is the difference between symmetric and asymmetric cryptosystems?
• What is a monoalphabetic cipher? How can one break a monoalphabetic cipher?
• What are the different types of attacks (and their relative power) on a cryptosystem?
• What is a one-time pad? How secure is a one-time pad?

There is a remarkably close parallel between the problems of the physicist and those of the cryptographer. The system on which a message is enciphered corresponds to the laws of the universe, the intercepted messages to the evidence available, the keys for a day or a message to important constants which have yet to be determined. The correspondence is very close, but the subject matter of cryptography is very easily dealt with by discrete machinery, physics not so easily.

Alan Turing

University of Virginia Department of Computer Science CS 551: Security and Privacy on the Internet

David Evans evans@virginia.edu