Password Encryption

Version 1.0

Introduction

Password Encryption is an encryption program that I wrote to encrypt info on my TI-89. I wrote the program mainly for fun and to explore some of the programming features of my TI-89. I had a program that did about the same thing on my TI-85, but it was much slower and did less in the way of encryption. I was able to write a much faster and stronger encryption program using the TI-89. My TI-85 encrypted at a speed of only about .25 characters per second, where as the TI-89 can encrypt at up to 8 characters per second on the lower encryption strength setting and 4 characters per second on the higher strength setting.

My program using a non-periodic polyalphabetic encryption method for the low strength setting. The high strength setting rotates the string a random number of elements each time that string is used for encryption. I am certainly not a cryptologist, but this method appears to be a one that is used in a few encryption systems. I know that the most widely used methods of encryption uses very large numbers, but I do not know that much about large number theory. I think that the TI-89/TI-92+ would be a good platform for an encryption program that used very large integers because of its native support for very large integers (2048 bit). I used the polyalphabetic encryption method because it was easy to program and I had already developed an algorithm for it.

Installation

To install Password Encryption just send the group file to the calculator, but make sure the retain folder option is checked in the Graph Link software.

To run the program change the current folder to pencrypt and type pencrypt().

How to use Password Encryption

The program is menu driven and very self explanatory.

Possibly Future Additions

A module that will convert the cipher text to a picture.

A setting that makes the program use only leters, numbers, and spaces instead of all of the characters so that it can be used for writing notes on paper.

Other

If you have any questions, comments, or figure out how to break the encryption I used email me at chrisdillard@cheerful.com.