Is there a reason TI didn't make the 84 Plus CE open to third party applications from the start? Was it like this when other TI calculators came out? Or did Texas instantly make it open when they released the other calculators?
As far as I heard they try to keep the key secret because the calculators are allowed for exams like they are now. However, third party apps open new possibilities for cheating and so on, and thet calculators could get forbidden.

But I am not completely sure, Kerm or maybe someone else explained that to me earlier.
The TI-84 Plus C Silver Edition wasn't open to Apps either: the community factored the 512-bit App key on that calculator and released it for general use. Probably due to the outcome of the key-signing controversy (ie, US law), TI Education did not choose to pursue the community over that factorization, and the community was able to release TI-84 Plus C Silver Edition Apps. On the newer TI-84 Plus CE, the App key is 2048 bits, which is many, many orders of magnitude harder to factor (many millenia on clusters of current hardware). I do know some of the reasons stated for why Apps have not been made easier for the community to create on the TI-84 Plus CE, and Cemetech has been working with the relevant parties to come to some kind of agreement that will make both the community and TI Education happy. We'll update you when we have more information we can share.

Nik wrote:
As far as I heard they try to keep the key sexret because the calculators are allowed for exams like they are now. However, third party apps open new possibilities for cheating and so on, and thet calculators could get forbidden.
That's inaccurate. Community Apps cannot do anything special that ASM programs cannot already do, in terms of potentially test-compromising functionality.
Quote:
TI Education did not choose to pursue the community over that factorization

Well, they had better not do that, lest they wanted to get lambasted in a very public manner one more time by the EFF and other organizations for performing another round of illegal attacks on legal content, aggravated by the fact that the complete illegality of their attacks was explained to them by an actual attorney several years before, and the law didn't change in-between Wink

Also, it should be mentioned that Cemetech isn't the only, or even the first, organization trying to find out solutions for both TI EdTech and the community of programmers and users to be happier.

Last but not least, nobody should get their hopes up about the feasibility and content of some kind of agreement making the TI-eZ80 series a more open, and therefore more successful, platform.
KermMartian wrote:
The TI-84 Plus C Silver Edition wasn't open to Apps either: the community factored the 512-bit App key on that calculator and released it for general use. Probably due to the outcome of the key-signing controversy (ie, US law), TI Education did not choose to pursue the community over that factorization, and the community was able to release TI-84 Plus C Silver Edition Apps. On the newer TI-84 Plus CE, the App key is 2048 bits, which is many, many orders of magnitude harder to factor (many millenia on clusters of current hardware). I do know some of the reasons stated for why Apps have not been made easier for the community to create on the TI-84 Plus CE, and Cemetech has been working with the relevant parties to come to some kind of agreement that will make both the community and TI Education happy. We'll update you when we have more information we can share.

Nik wrote:
As far as I heard they try to keep the key sexret because the calculators are allowed for exams like they are now. However, third party apps open new possibilities for cheating and so on, and thet calculators could get forbidden.
That's inaccurate. Community Apps cannot do anything special that ASM programs cannot already do, in terms of potentially test-compromising functionality.


How much years in CPU time would we need to factor the 2048 bit key? It would be interesting project to build a super computer out of calcs and use them to crack the code Smile.

Edit: Just saw the many millenia of years on current clusters of hardware...then I did a bit of research and Kerm is right, there is no way we can crack it unless we solve a mathematical problem that someone put up $200,000 in hopes of a solution.

For example this is a 2048 bit number: RSA-2048 = 2519590847565789349402718324004839857142928212620403202777713783604366202070
7595556264018525880784406918290641249515082189298559149176184502808489120072
8449926873928072877767359714183472702618963750149718246911650776133798590957
0009733045974880842840179742910064245869181719511874612151517265463228221686
9987549182422433637259085141865462043576798423387184774447920739934236584823
8242811981638150106748104516603773060562016196762561338441436038339044149526
3443219011465754445417842402092461651572335077870774981712577246796292638635
6373289912154831438167899885040445364023527381951378636564391212010397122822
120720357
Even 1024-bit RSA keys are well out of the reach of small-ish groups of individuals like us. The current record, RSA-768, was set by the leading researchers of the integer factoring field from 2006 to 2009, using academic-scale resources - and the paper states that RSA-1024 is about a thousand times harder. The paper also states that the factorization of one 1024-bit RSA key is likely to be performed before 2020, though.
Without a computational breakthrough, RSA-2048 won't be within reach before the 2030s or 2040s.

TL;DR: don't bother: it's so many orders above what can be reached using calculators that it isn't funny...
Someone could write an assembly program that "patches" whatever part of TI-OS reads apps to make it use a different 2048-bit signing key which is known. The apps that are shipped with the calculator would of course have to be decrypted using the key in the OS and then encrypted again using the new key. (I'm not a super crypto-nerd so I could be very wrong about all of this.)
Hactar wrote:
Someone could write an assembly program that "patches" whatever part of TI-OS reads apps to make it use a different 2048-bit signing key which is known. The apps that are shipped with the calculator would of course have to be decrypted using the key in the OS and then encrypted again using the new key. (I'm not a super crypto-nerd so I could be very wrong about all of this.)


Yes, this has already been done. Of course, it is super hackish and means different versions across OSs, which is not very user friendly. Another option would be to create an app directly from an assembly program; again, this is technically not sane or applicable in this case.
Hactar wrote:
Someone could write an assembly program that "patches" whatever part of TI-OS reads apps to make it use a different 2048-bit signing key which is known. The apps that are shipped with the calculator would of course have to be decrypted using the key in the OS and then encrypted again using the new key. (I'm not a super crypto-nerd so I could be very wrong about all of this.)

I'm no expert either but I believe I recall Kerm (not quoting anything here) saying that we cannot "dissassemble" apps and that it is illegal to modify the OS itself. Also, I think that if it were that easy to modify the OS, we would probably have heard of some people doing it illegally, I mean like most things, if it's forbidden, there are people who will do it. However, this is not the case and I have never heard of anybody even attempting to modify the OS itself, therefore, I am assuming it's not feasible/possible. On top of that, I think that if you're at the point where you can change the encryption key all together, you've probably managed to figure the original one out without the use of brute force techniques.
mr womp womp wrote:

I'm no expert either but I believe I recall Kerm (not quoting anything here) saying that we cannot "dissassemble" apps and that it is illegal to modify the OS itself. Also, I think that if it were that easy to modify the OS, we would probably have heard of some people doing it illegally, I mean like most things, if it's forbidden, there are people who will do it. However, this is not the case and I have never heard of anybody even attempting to modify the OS itself, therefore, I am assuming it's not feasible/possible. On top of that, I think that if you're at the point where you can change the encryption key all together, you've probably managed to figure the original one out without the use of brute force techniques.


What? Of course modification of the OS is possible; and is quite simple if you know what you are doing. ZStart was a prime example of such a program back on the monochrome calculators. The process for adding a key is much like the Free83p program by BrandonW back in the day. Of course, none of these tools are needed, because it is perfectly fine to stay within the imposed restrictions in place. The legality of a lot of these things is certainly questionable, which is why disscusion has been very limited after the 2009 madness. Note that it is also against the end user agreement to use an emulator outside of TI, but no one seems to bring that one up Wink
MateoConLechuga wrote:
mr womp womp wrote:

I'm no expert either but I believe I recall Kerm (not quoting anything here) saying that we cannot "dissassemble" apps and that it is illegal to modify the OS itself. Also, I think that if it were that easy to modify the OS, we would probably have heard of some people doing it illegally, I mean like most things, if it's forbidden, there are people who will do it. However, this is not the case and I have never heard of anybody even attempting to modify the OS itself, therefore, I am assuming it's not feasible/possible. On top of that, I think that if you're at the point where you can change the encryption key all together, you've probably managed to figure the original one out without the use of brute force techniques.


What? Of course modification of the OS is possible; and is quite simple if you know what you are doing. ZStart was a prime example of such a program back on the monochrome calculators. The process for adding a key is much like the Free83p program by BrandonW back in the day. Of course, none of these tools are needed, because it is perfectly fine to stay within the imposed restrictions in place. The legality of a lot of these things is certainly questionable, which is why disscusion has been very limited after the 2009 madness. Note that it is also against the end user agreement to use an emulator outside of TI, but no one seems to bring that one up Wink

Well I mean, apparently it isn't perfectly fine because the community can't make apps! Razz
And I really didn't know this was possible, I thought programs like ZStart were just adding in keyhooks like Doors (which as far as I know, aren't modifying the OS directly...) Also, why do people not use these more? If I could modify the OS, I know there are a bunch of things I would chnage/add! XD
mr womp womp wrote:
If I could modify the OS, I know there are a bunch of things I would chnage/add! XD

Changelog:
    9+10 now equals 21
    Changed the graph screen to a video player
    Removed app limitations
    Enabled ASM apps to run without using Asm(
    Added DoorsCE as a permanent part of the OS.
    Got rid of the calculator functions
    Installed Linux
KingInfinity wrote:
mr womp womp wrote:
If I could modify the OS, I know there are a bunch of things I would chnage/add! XD

Changelog:
    9+10 now equals 21
    Changed the graph screen to a video player
    Removed app limitations
    Enabled ASM apps to run without using Asm(
    Added DoorsCE as a permanent part of the OS.
    Got rid of the calculator functions
    Installed Linux

OMFG THIS THO :'))))
But in all seriousness, I was referring to some things that I think would make calculators generally better without actually compromising anything... kinda like this
    Lowercase/APD toggling
    integrated conics/3D graphing *winks at Kerm Wink*
    Placing the clock on the homescreen (why is this not standard!!!)
    Adding a menu for Greek letters in the VARS menus and the "" symbol in the catalog.
    Fixing the Y= bug on the CSE (this one seems particularly awkward)
    Enable ASM apps to run without using Asm( (this should have been this way from the start...)
    Enable Archived programs to run without having to unarchive them (same idea)
    Making it so that one can ALPHA + Letter in the MEM Management menus (like in most other menus)
    Get the solver to display all solutions e.g., (χ^2)-3=0, χ=√3 or χ=1.73 (not sure if this would require a CAS, but if it doesn't, why not!)
    Adding a bunch of the libby functions that desperately need tokens (ToSting, ExecAsm, StringWidth, etc.)

For the libby (yes thats a new word, should be in the dictionary Razz) functions, I think I would stay away from the drawing commands and the half-res mode stuff because I would want to keep ti-basic as a simple language that doesn't require any kind of programming skill to learn easily, because I know for a fact that this is what people who have just purchased a graphing calculator love about ti-basic.
I'm sure If I were actually doing this, that I would be able to think of a zillion more things that could/should be done, but these are the major things I could think of right off the top of my head Razz
mr womp womp wrote:

Enable ASM apps to run without using Asm( (this should have been this way from the start...)
Enable Archived programs to run without having to unarchive them (same idea)
I've strongly suggested both of these to our TI friends; I'll do my best to find out if they're considering them as possible OS 5.x modifications.
mr womp womp wrote:

    Lowercase/APD toggling
    integrated conics/3D graphing *winks at Kerm Wink*
    Placing the clock on the homescreen (why is this not standard!!!)
    Adding a menu for Greek letters in the VARS menus and the "" symbol in the catalog.
    Fixing the Y= bug on the CSE (this one seems particularly awkward)
    Enable ASM apps to run without using Asm( (this should have been this way from the start...)
    Enable Archived programs to run without having to unarchive them (same idea)
    Making it so that one can ALPHA + Letter in the MEM Management menus (like in most other menus)
    Get the solver to display all solutions e.g., (χ^2)-3=0, χ=√3 or χ=1.73 (not sure if this would require a CAS, but if it doesn't, why not!)
    Adding a bunch of the libby functions that desperately need tokens (ToSting, ExecAsm, StringWidth, etc.)

It's funny because you've basically described a few features of the TI-Nspire CX CAS (also valid for the 68k models as well).
KermMartian wrote:
mr womp womp wrote:

Enable ASM apps to run without using Asm( (this should have been this way from the start...)
Enable Archived programs to run without having to unarchive them (same idea)
I've strongly suggested both of these to our TI friends; I'll do my best to find out if they're considering them as possible OS 5.x modifications.

Yeah this is both confusing for beginners and seemingly useless Smile
These calculators were made to be as useful and simple to use as possible and the fact that you need to *learn* these things that could be done by the OS goes against that, A user friendly machine should do as much as possible to make a user's life simpler.
Adriweb wrote:
mr womp womp wrote:

    Lowercase/APD toggling
    integrated conics/3D graphing *winks at Kerm Wink*
    Placing the clock on the homescreen (why is this not standard!!!)
    Adding a menu for Greek letters in the VARS menus and the "" symbol in the catalog.
    Fixing the Y= bug on the CSE (this one seems particularly awkward)
    Enable ASM apps to run without using Asm( (this should have been this way from the start...)
    Enable Archived programs to run without having to unarchive them (same idea)
    Making it so that one can ALPHA + Letter in the MEM Management menus (like in most other menus)
    Get the solver to display all solutions e.g., (χ^2)-3=0, χ=√3 or χ=1.73 (not sure if this would require a CAS, but if it doesn't, why not!)
    Adding a bunch of the libby functions that desperately need tokens (ToSting, ExecAsm, StringWidth, etc.)

It's funny because you've basically described a few features of the TI-Nspire CX CAS (also valid for the 68k models as well).

Yes, but I feel that the nspire is a long way away from the good old ti-84, it looks like they made a big leap that resulted in calculators about as complicated to use as computers and a little buggy as well (To someone who has never used a computer, of course it is quite complex). The modified OS that I am thinking of still remains in the same feel as the older calcs, with just some random tweaks Smile. Don't want to grumble on about the nspire either because honestly, it is a wonderful calc for algebra and calculus and I personally am learning to use it more and more as I go through the different levels of education.
Quote:
Enable ASM apps to run without using Asm( (this should have been this way from the start...)
Enable Archived programs to run without having to unarchive them (same idea)

The TI-68k series has these features. We'll see whether the TI-eZ80 series, which is closer to the TI-68k series, grows them at some point.
Idea: What if your just overcomplicating things. I mean, TI has released a new OS update for the TI-84 plus CE, so why not just see how the TI connect program loads the file onto the calculator to obtain the access key? In theory, it should work, I guess.
Pepperester wrote:
Idea: What if your just overcomplicating things. I mean, TI has released a new OS update for the TI-84 plus CE, so why not just see how the TI connect program loads the file onto the calculator to obtain the access key? In theory, it should work, I guess.

Let's not try to hack TI's methods. Like I said, there's probably a very good reason they don't release them.
Guys, there is simply no way to get the private signing key from TI, unless you burgle in or whatever. If you still think that, read something about public cryptography.
  
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