List Detection

[Jeffrey]

In short, I am creating a program that I will, eventually, sell to people at my school. To prevent people from trading this program without unauthorization via a link cable, I am implementing an encrypted list that the program (when it installs) will create. Upon program startup the program will check for the list and make sure the data is the same (if it is the same calculator). Confused yet? Well here is the question:

Is there a way to check and make sure if the list given (i.e. listSETUP) is a valid one. Like if I used:

If listSETUP(1)=10

and listSETUP didnt exist, I would get an error. Get what I am saying?

[yugniht]

how about this

[Arcane Wizard]

Wouldn't they just be able to edit that code out of it ?

[Babyboy]

couldent they also just trade the installer file?


also, you arent going to sell a game in a school unless A. it is a full 3D trigun game in a room full of raging Otaku's. B.your selling it for 5c. C. your school is full of people made of money. D. it is the most graphicly and gameplay advanced game in the world of calculators, like an exact clone of FF7.



just my thoughts, Babyboy

[Arcane Wizard]

I think he means they would just be able to install the program using a proper 'key' and then give all the installed stuff to other people so they won't have to buy it from you.

As for selling Basic games, I don't think you'll have much look trying that, but good luck anyway.

p.s. I also wonder if it's legal to sell TIBasic programs. (without some license or agreement from TI)

[David]

As long as you have created yourself, I don't see any problem with that

[Darth Android]

if u go to Cirrus and look up "ID2Str" under asm misc. prgms, u can use it to get the first 10 digits of the user's calculator's personal ID #/code. using ptools from cirrus and putting

[Tyler]

Never use a list for varification! Theres got to be at least two or more Ti nerds in every school and they would spread the truth just to send the list with the program, or at least thats my thoughts!

Hope it helps, Tyler

[Adm.Wiggin]

you could make an asm program to hide the list

[62 52 53 53]

...or encrypt the ID nums in a list, then delete the installer. I'm hope to make cert programs. they would do the following. certificate program(first program name) would be the cert. This would contain common routines necessary for the program. The installer program(second program name) would hide it, convert it to an appvar, (hopefully even encrypt it using the calculator ID as the encryption key), and archive it, before deleting itself. program(program name three) would get the cert by doing di, coppy the avar to ram, decrypt it, convert it to a prog, interrupt the on key, and install program( name four) to run on calculator activation via offscrpt, run the program, delete it, and EI. The main program would require these routines and not work if unavailable.

Security would be enforced by the following things:
custom certs: different certs would be incompatible(wrong routines)
encrypted first line: the first line of the prog would be checked by the installer to make sure it was the right prog
different cert names: need the right name
different runners: each running program would store something as a var, and the cert would check this, delvar, and terminate if not the right thing
hidden certs: hard to find
ID encryption:transfer requires decryption and re-encryption
different encryption: different certs would have different encryption methods using the ID
avar: must be converted to program
interrupt on: prevents on breaks from preventing program deletion
in ram: if batteries pulled, the program is deleted
offscrpt program: if the batts are pulled and memory prot enabled, deletes prog
DI: interrupts can't tell what the prog is doing, or coppy it

These routines could probably be sold because:
each one would have built in anti-theft(compromisable by some ASM programmers, who would write de-installers) (or anyone who grouped/transferred them, so I would have to install via silent linkage instead)
nobody could share the routine they bought because it would compromise thier security
different certs would not work in place of eachother

[Spyderbyte]

Why not just save all the hassle and encourage people to trade it? There are plenty of games out there, so you could probably only sell it to a few people.

Besides, many people have put far more time and effort into something they just give away. (cough)NIMBUS

Just my two cents worth (no pun intended)

Spyderbyte

[NETWizz]

Well, do whatever you wish, but if you are not going to give away what you create, you may as well go with the established system.

Make it an app, and pay TI to sign it Software and let you then distribute it to run only on calculators with certain ID #'s.

If you do not want to pay TI to sign it, you can always ask Michal Vincet for the software key file. I am sure he took the time to pillage through all of TI's files while he wrote an app for them; therefore, I would venture to guess that he knows much about the entire app header format, workarounds, resigning a software app as freeware , et cetera.

Still, I do not think he will talk easily.

If you do sign an app software, why not make evaluation versions where the header is modified to delete the app after a limited number of executions. Sience it will be signed for only one calculator, I do not think people will continue to evaluate.

Now for the question of the day, why would anyone pay for calculator software when they can get it free?

[62 52 53 53]

I probably wouldn't sell my progs, except (maby)as a means of making sure that people didn't just use it in every single program. It would be good(and widely accepted) for some progs however, (not yet released ones, or ones with Ill effects.

[Spyderbyte]

[62 52 53 53]

First:
You would need to be an assembly programmer to bypass it. They couldn't just remove the line that ran the routine because if they did, an important segment would be missing. Make a program, then delete some random lines, and see what it does. You would need to do asm to get the routine onto the computer, and the asm could manipulate the variable so that you would put the wrong routines in the wrong places if you couldn't decompile it.

Second:
Yes, I know skilled assembly programmers could bypass this, so it would only work as a means of selling programs if no assembly programmers had access to a comp with the program and the appvar (unless they had incentive to not decompile it).

Third:
I said the routine could be sold, because it was rather secure. However, I would not sell it, merely audit the prog so that it was not overused. (and take a copy for myself, and maby distribute it to a few friends. Remind me to make sure they don't distribute it to anyone else, or if i'm giving it to you, you probably don't want me to make sure.)

Fourth:
My actual intent for this is something that would protect alpha/beta progs from espionage. Any programs you made could be set up so that people could not take them, as long as the owner of the calculator they were on(yours in this case) didn't want anyone to have them, even if the programs were stolen they wouldn't work.

[Pascal]

How about you use a Key? Write down a list of keys , and have a complex algorithym that will tke that key mulitly divide and square root or whatever multiple times until it comes to an answer of say, 1. If it is anyting else, the calcwon't exicute the program. Howwill we prevent people from editing it. FIrst, lock the program. This will stop the first wave of geeks that are to stupid to unlock a program. Second, use a system I invented a loooong time ago called "flow". all you do is delete all the spaces between code lines, until your entire code is one big long paragraph of code. each command is separated by a colon ":". When someone edits the program, they will not have the time or effort to look at the big garbled mess of code, nor have the time or effort to include the spaces again. Your algorithim could be separated into chunks spread thought the program. So the algorithm begins "enter key". You enter the key, then then in the code, it jumps to anothew lable, does another operation, jumps to a different lable, then does another operation jumps to another lable, and so on, until the algorythim is comple. Compare the result to 2 or 1 or whatever the result number is (could be something like 2.3452 or some complex number lke 3.6i). Finally add "dirty traicks to your code. dirty trick is to say cheack that the the comaring key number is 2.3452, if it was changed to any number, then the program will not run. Or if a key had not been entered, and the whole algorithy somehow bypassed, the missing key will still be needed ( the key number plus another will be need to go to osme lable or something. In short you programwill be un crack able. It iwll be wuick to do.

One more thing. If someone opens you calcultor program on say, graphink. It may be easiy to edit right? wrong. Since you code is all connected, the entire program is all one line! so on graphic you would need to endlessly scrol to the right. and edidting would be even harder on the computer.

[Adm.Wiggin]

thats funny Pascal! it would be great to see the look on the little geeks face when he looks at the prgm source, and sees one big long line!

[JesusFreak]

would that run faster with the flow system or would having a enters runfaster?

Why would you sell a prgm, don't you want ppl to know that you made that?

[Jeffrey]

Well, see no one at my school is smart enough to figure out how to change a list element (unless they looked in the book). In fact, people at my school have no clue what BASIC is, so it shouldnt be a problem. And this program probably would only be circulated in the school, not online.

As to selling the prog, well, I have had second thoughts. I personally, do not want to sell it, because that might be a little bit too much toward a Microsoft situation that makes $500 software that is worth maybe $5, and I do not want to be the Microsoft of my school. Basically my friend said: "Hey, you could sell that program" and an idea popped into my head. So I have decided I wont sell it, I'd rather give it away.

The idea came up, though, because my most popular program is a formula bank, and that is something people would be willing to pay for (lol, answers to algebra worksheet:$1. Answers that show work:priceless).

Yep, so now I wont sell it, but maybe this system will help prevent other people from selling it after I give it away. Thanks!

[Adm.Wiggin]

Just dont accidently press clear while on the one line! that would be wayy too bad!