1. Cryptology
Day 3: First look at
computer ciphers
MAT 140: Introduction to the
Mathematical Sciences
19 September 2008
Robert Talbert, PhD
Associate Professor of Mathematics
and Computing Science
rtalbert@franklincollege.edu
2. Recap of Day 2
• Integer congruence modulo n
• Using integer congruence to make and break shift ciphers
• Idea: Representing text characters as numbers and then
using math to manipulate them
3. Unicode
Worldwide standard for
representing characters from the
keyboard and various languages
in numerical form