CX 103: Introduction to Computers

Spring 2001

Assignment 25

Due: Friday, April  20

Reading

Finish reading Chapter 9 "Fire and Ashes" in Freiberger and Swaine, Fire in the Valley: The Making of the Personal Computer.

Begin reading Chapter 23: "Electronic Commerce and Security" in Deitel, Deitel & Nieto, Internet & World Wide Web: How to Program.
 
 

Programming Exercise
Due: Monday, April 23

Modify our program Encryption.html to use trios of three successive characters. Each triple is initially replaced by a six digit number. We then add some fixed number S % 10 to each digit (we used S = 7 before) and finally we reverse the order of the digits of the new 6 digit number.

Allow the user to specify the value of S when the program is run. Handle input and output through forms.

Bear in mind that we may eventually want to encrypt by taking blocks of 4 consecutive characters or 5 consecutive ones, etc. Let this ultimate goal guide you in your formulations.

Writing

Write up a reasonably detailed algorithm in pseudo-code format for implementing the computing dating algorithm. You will want to find the closest match to your answers. You may assume that all the data has been declared and initialized in the form of arrays as discussed in the lectures.