This is the second release of my cryptography software for the TI-92. The most important new features are the use of "shadow" keys, the new encrypt formula which is a little more secure, a local on-calculator "manual", and a revamped program structure.
The "shadow key" functionality has been added to this release. It protects the user from having their data easily cracked. Now, instead of having the user have only 1 key, they have a second "random" key!
The new formula is slightly more secure, but the advanced formula has not been finished, so you won't see it until BETA 3.
There is now an on-calculator manual, for those of you who use your calculator in school, I have included a miniature manual in the format of a 92 text file.
I also completely re-wrote the entire client and library, so that it would be easier to incorporate into other TI-BASIC programs and save space.
Once again, I do not believe that this cryptography scheme can be easily cracked, but I do not guaruntee it. IN NO WAY AM I LIABLE FOR ANY LOSS OF DATA OR DAMAGES THAT OCCUR FROM USE OF THIS PROGRAM. I have not found any "bugs" in this program, but please note that if you forget your key or the shadow key, the data will not be recoverable!
Crypt was designed so that the technology behind it could be integrated into other TI-BASIC programs without the programmers knowing how the cryptography code works. If you would like to know how to use my cryptography schemes in your program, please send me an email at prgmrChris@email.com
My name is Chris Marsalo, and I have been programming for 3 years. I started with Apple BASIC, and I am now proficient in QBasic, Visual Basic, and C++ as well as TI-BASIC on TI-82's and TI-83's. I have been doing calculator programming for about a year and half. I am 16 and a sophomore in high school. I am very familiar with computer hardware (meaning I built all 4 computers in my house myself), and am pretty good at programming. Also, I know a decent amount of Linux and UNIX. If you are trying to learn how to use either one and having trouble then email me. I currently run a Win95/BSDI UNIX 3.1 dual boot, and fell in love with BSDI UNIX, when I realized how much better it ran than Windows, and I haven't had to reboot nearly as much. I own a TI-82, TI-83, and TI-85. Anything else feel free to email me. Now that I own my own Graph-Link, I will be releasing alot more TI-BASIC programs, and maybe some assembly if I get good enough. If anyone is interested in helping me writing an assembly version of CRYPT for the TI-68k graphing calculators, I would greatly appreciate it if you would email me. I would also like to mention that this was written without me having the manual. I do not own a TI-92, but I borrowed one from someone so I could write this and test it. I learned how to use the TI-92 BASIC commands by viewing the parameters that are displayed in the catalog. I do believe that TI-92 BASIC supports error handling, but it was not implemented in this version, because I haven't learned it yet!
The next release of Crypt92 will have the layering feature, and A much better form of cryptography, using more dependance on the the original and shadow keys. Look out for my Z80 assembly version for the TI-82, which I may port myself to the other Z80 calculators, or hopefully someone else will. I could really use some help in the assembly department, so please email me if you have written programs that access external variables. My biggest problem in the Z80 version has been displaying a list of the used variables. For example, the matrices that actually have data in them. So far the program works ok, but sometimes it crashes and resets the memory. I have not released it, because it is way too unstable, and I would be embarrassed to release it in this state. My email address is: prgmrChris@email.com
11/3/2000 - First public release
12/1/2000 - BETA 2
Added on-calc manual, shadow keys, slightly better formula, and re-designed program structure to save space and provide easier use and incorporation.