CITA-250: Information Security
American University in Bosnia and Herzegovina Spring 2009
Agenda
Course Introduction Syllabus
http://sites.google.com/a/aubih.edu.ba/cita-250/syllabus
Philosophy, Language, and Computer Security Introduction to Computer Security
Break
Course Introduction
Walk through the Syllabus
If we do this properly, this will be the most fun
class you have in college!
If we do this improperly, I will be fired or
imprisoned and you will be expelled!
We get to break things!
Repeat: we get to break things!
Caveat: we must be exceedingly careful
Philosophy and Computer Security
Many of the topics we will discuss in this class
have analogues in:
History
Linguistics
Philosophy
Computer and information security raises
fundamental questions regarding language.
Specifically: is the purpose of language to
What am I really trying to say?
Fact 1: I love my Mother
Fact 2: My Mother is not a very good cook Fact 3: My Mother likes to cook for me
Question: My Mother asks me if I like dinner. Response: This is wonderful! Thank you.
Fact 4: I spend several days in the hospital after
dinner at my Mother's house.
Analysis: When I exclaimed “This is wonderful!”,
Shibboleth
Book of Judges. The full account is in Chapter 12, verses 1-15.
“Then said they unto him, Say now Shibboleth: and he said Sibboleth: for he could not frame to pronounce it right. Then they took him, and slew him at the passages of Jordan: and there fell at that time of the Ephraimites forty and two
thousand.”
See Professor Kemmer's Website for full background
Shibboleth as Linguistic Password
Linguistic password that serves to
Include speakers of a certain dialect
Exclude speakers of other dialects
Sienese Shibboleth
This is an example of language serving as a security
mechanism
Sadly this technique has been used frequently
throughout history to hurt people who were different
Note: the meaning of the word did not matter in this
Language and Compression
Most languages use compression to convey
more meaning in less time
Contractions: do not becomes don't
Acronyms: NIMBY
Poetry is a highly compressed form of language
Haiku: only 17 syllables
Language and Compression
Haiku Computer Error Messages http://www.infiltec.com/j-chaiku.htm
Seeing my great fault
Through darkening blue windows I begin again
- Peter Rothman
Best essay ever about technology and its
influence on the English language is:
George Orwell, Politics and the English
Language
Language and Encryption
Caesar Cipher Example:
Language and Encryption
Online substitution ciphers
http://www.simonsingh.net/The_Black_Chamber/caesar.html
In addition to simple encryption techniques, the
ancients also used steganography to hide messages
Examples from Herodotus
Covering wooden panels with wax
Tattoo message on scalp (hair covers it)
Riddles and Security
Riddle of the Sphinx
What walks on four legs in the morning, two
legs at noon, and three legs in the evening?
Humans
Sphinx protects Thebes
If traveller answers incorrectly, sphinx kills her
If traveller answers correctly, sphinx kills
herself
Language and Security
Encrypted names
provide security when criticizing authorities
666 stands for
Roman Emperor Nero
Author of Revelations
could not openly attack an Emperor
He encodes the name
Paradox, Ambiguity, Euphemism
Liar's Paradox: I am lying.
If true, you cannot believe the statement...
If false, you cannot believe the statement...
Gödel's proof adapted the Liar's paradox to
numbers
Ambiguity: when words have more than one
meaning...
Language, Technology, and Security
Humans developed technology for a variety of
reasons
Perhaps the most pressing reason is security Our language and history demonstrate that we
use security mechanisms frequently:
Passwords
Compression
Encryption
Language, Technology, and Security
Computer Security and Information Security
simply expand on these concepts
We will explore how these concepts were
applied to the new technologies of our day
As we explore the details of this subject, please
attempt to connect these details to the big picture
What is the purpose of technology?
References
http://www.ruf.rice.edu/~kemmer/Words/shibboleth.html
http://www.infiltec.com/j-chaiku.htm
http://en.wikipedia.org/wiki/Caesar_cipher
http://en.wikipedia.org/wiki/The_Number_of_the_Beast
http://mathworld.wolfram.com/LiarsParadox.html
