Login [Register]
Don't have an account? Register now to chat, post, use our tools, and much more.
This is an archived, read-only copy of the United-TI subforum , including posts and topic from May 2003 to April 2012. If you would like to discuss any of the topics in this forum, you can visit Cemetech's Technology & Calculator Open Topic subforum. Some of these topics may also be directly-linked to active Cemetech topics. If you are a Cemetech member with a linked United-TI account, you can link United-TI topics here with your current Cemetech topics.

This forum is locked: you cannot post, reply to, or edit topics. Community News & Discuss Nspire => Technology & Calculator Open Topic
Author Message
smblackh


Newbie


Joined: 06 Nov 2010
Posts: 13

Posted: 06 Nov 2010 12:35:45 pm    Post subject:

I know of Ndless, but so far the only stable version supports OS 1.1, which doesn't work well due to the glitches turning it on, and it is still based off of TI's default operating system. Mad Yeah, the TI-84 and others support 3rd party OS's, but what can you get with a 15 Mhz processor and 1.5Mb of archive? With the Nspire theres possibilities of a real functional 3rd party OS, like some form of Linux!!!
Brute forcing is not much of an option, the RSA key is a 1024 bit (309 digit) monster. (Hackspire has some more info)
Factoring that with brute force would take centuries. Does anyone have any ideas?
Back to top
Levak


Advanced Newbie


Joined: 11 Nov 2009
Posts: 94

Posted: 06 Nov 2010 01:00:19 pm    Post subject:

Phryzly wrote:

Does anyone have any ideas?


Wait ?
Laughing
Back to top
smblackh


Newbie


Joined: 06 Nov 2010
Posts: 13

Posted: 06 Nov 2010 07:47:37 pm    Post subject:

Maybe when every computer has 192 cores and a clock speed of 8 Ghz... Neutral I actually programmed myself a program to brute factor it (too stupid to understand/program anything else right now) that supports multicore. I made it notify me when it was 0.000000000001 percent done and after 2 minutes of waiting and nothing happening I gave up. So assuming it was done in 2 minutes, that means this program will take around 380,250,000 years to complete...
Back to top
yifanlu


Newbie


Joined: 21 Mar 2010
Posts: 15

Posted: 07 Nov 2010 02:25:47 pm    Post subject:

The old TI calculators was cracked "easily" (and by easy I mean hundreds of volunteers contributing CPU for weeks) because the key was only RSA-512. The nspire has RSA-1024 with is twice as long, therefore 2^512 times longer.
Back to top
smblackh


Newbie


Joined: 06 Nov 2010
Posts: 13

Posted: 07 Nov 2010 06:30:33 pm    Post subject:

Yes the Nspire key would take much longer to crack meaning much more advanced and complex methods have to be used. If GNFS (General Number Field Sieve) was used, this would take around two months or so with community support, but GNFS is a very complex method to program.
Back to top
Lionel Debroux


Member


Joined: 01 Aug 2009
Posts: 170

Posted: 08 Nov 2010 12:32:33 am    Post subject:

(emphasis mine)
Quote:
If GNFS (General Number Field Sieve) was used, this would take around two months or so with community support, but GNFS is a very complex method to program.

No way. Even the leading-edge implementations of GNFS + post-processing that allowed factoring RSA-768 (in much more than two months) are, AFAICT, not public at the moment, and RSA-1024 is said to be at least one thousand times harder.
For more information, see:
* the long http://www.omnimaga.org/index.php?topic=3639.0 thread on Omnimaga, about the same topic;
* for the factoring community side of the story, see e.g. http://blogs.rsa.com/juels/rsa-768-factored/ and http://www.mersenneforum.org/showthread.php?t=12958
Back to top
smblackh


Newbie


Joined: 06 Nov 2010
Posts: 13

Posted: 08 Nov 2010 06:58:22 pm    Post subject:

Oh crap. Looks like I completely screwed up my calculations. Then this means the only way to crack the key would be to implement a virus during the install of a new OS.
Back to top
calc84maniac


Elite


Joined: 22 Jan 2007
Posts: 770

Posted: 08 Nov 2010 07:28:03 pm    Post subject:

Phryzly wrote:

Oh crap. Looks like I completely screwed up my calculations. Then this means the only way to crack the key would be to implement a virus during the install of a new OS.

The OS doesn't hold the key we need to sign our own OS's, just the one needed to validate OS's. We're not going to get the key that way.

Though, if we find an exploit in the boot code that will force it to run an OS without validating it, that would work for our purposes Smile
Back to top
xtjacob


Newbie


Joined: 15 Oct 2009
Posts: 17

Posted: 07 Dec 2010 10:02:19 pm    Post subject:

calc84maniac wrote:

Phryzly wrote:

Oh crap. Looks like I completely screwed up my calculations. Then this means the only way to crack the key would be to implement a virus during the install of a new OS.

The OS doesn't hold the key we need to sign our own OS's, just the one needed to validate OS's. We're not going to get the key that way.

Though, if we find an exploit in the boot code that will force it to run an OS without validating it, that would work for our purposes Smile



This is a crazy idea, but then again there are people who will do anything to crack their calculators. What if we tried something like this: http://www.engadget.com/2010/03/09/1024-bit-rsa-encryption-cracked-by-carefully-starving-cpu-of-ele/ or something like this http://techie-buzz.com/tech-news/1024-bit-rsa-cracked.html. I know they're crazy idea's, but I would love to see the look on TI's face if we manage to do something like this... If somebody can help me with this I do have a SPARC computer laying around. Smile
Back to top
Xeda112358


Active Member


Joined: 19 May 2009
Posts: 520

Posted: 08 Dec 2010 01:46:00 am    Post subject:

Ooh, wow, that is a very neat idea. I still want to attack prime numbers with the absolute brutal force of my mind, but I guess for now that could be useful. I think it will be more fun to create an algorithm to factor 2048-bit semi-prime numbers, though, in a timely manner. I am working on it! :D

Well, when I am bored or have nothing better to do...
Like the Riemann Hypothesis... Razz


Last edited by Guest on 08 Dec 2010 11:18:54 pm; edited 1 time in total
Back to top
Goplat


Advanced Newbie


Joined: 26 Jun 2007
Posts: 95

Posted: 08 Dec 2010 01:30:59 pm    Post subject:

xtjacob wrote:

This is a crazy idea, but then again there are people who will do anything to crack their calculators. What if we tried something like this: http://www.engadget.com/2010/03/09/1024-bit-rsa-encryption-cracked-by-carefully-starving-cpu-of-ele/ or something like this http://techie-buzz.com/tech-news/1024-bit-rsa-cracked.html

This "crack" requires physical access to the computer with the private key, so it's pretty useless.
Back to top
xtjacob


Newbie


Joined: 15 Oct 2009
Posts: 17

Posted: 08 Dec 2010 05:16:59 pm    Post subject:

Goplat wrote:

xtjacob wrote:

This is a crazy idea, but then again there are people who will do anything to crack their calculators. What if we tried something like this: http://www.engadget....ing-cpu-of-ele/ or something like this http://techie-buzz.c...sa-cracked.html

This "crack" requires physical access to the computer with the private key, so it's pretty useless.


Oh, I guess I misread it then... Razz
Back to top
Xeda112358


Active Member


Joined: 19 May 2009
Posts: 520

Posted: 08 Dec 2010 11:20:44 pm    Post subject:

Aww, but the article is still pretty cool! At least that means we still have an excuse to play with primes!

I ♥ Math! (and yes, that is a factorial)
Back to top
willrandship


Newbie


Joined: 16 Dec 2009
Posts: 10

Posted: 21 Jan 2011 05:38:41 pm    Post subject:

I hope this isn't too much of a necropost...some places have different rules regarding that.

I had a different idea, that I am rather unable to pursue not knowing any Arm Assembly, or even z80 assembly :P

At hackspire, there is a text file logging the communication over RS232 during startup of an nspire. In all types of startup (maintenance menu access, standard, deleting OS, etc.) there is a small list that is always the same.

Note that this is version 1.1 of the boot2, but since this is coming from the boot1 as well, it doesn't matter.

Boot Loader Stage 1 (1.1.8916)
Build: 2007/4/23, 23:37:16
Copyright (c) 2006, 2007 Texas Instruments Incorporated
Using production keys

Now, why say that if that is the only possible outcome? There is a possibility that there is a way to force the calculator to use other RSA keys for checking than the ones it comes with, or maybe even none at all. This might be though the serial, through some config file, or any number of different ways, but there must be some way to use this.

My idea is to look through the disassembled Boot2 code, and find what it does prior to outputting the fated serial message "Using Production Keys"

What do you think?
Back to top
Goplat


Advanced Newbie


Joined: 26 Jun 2007
Posts: 95

Posted: 21 Jan 2011 10:07:03 pm    Post subject:

That message doesn't mean anything. The code is just doing


Code:

print("\n\n\n\r");
print("Boot Loader Stage 1 (1.1.8916)\r\n)");
print("Build: 2007/4/23, 23:37:16\r\n");
print("Copyright (c) 2006, 2007 Texas Instruments Incorporated\r\n");
print("Using production keys\r\n");
print("\n");


Nothing more.
Back to top
willrandship


Newbie


Joined: 16 Dec 2009
Posts: 10

Posted: 22 Jan 2011 02:05:40 pm    Post subject:

but why say it at all if it's always that way? Are you sure that's all it can do?
Back to top
Display posts from previous:   
Register to Join the Conversation
Have your own thoughts to add to this or any other topic? Want to ask a question, offer a suggestion, share your own programs and projects, upload a file to the file archives, get help with calculator and computer programming, or simply chat with like-minded coders and tech and calculator enthusiasts via the site-wide AJAX SAX widget? Registration for a free Cemetech account only takes a minute.

» Go to Registration page
    »
» View previous topic :: View next topic  
Page 1 of 1 » All times are GMT - 5 Hours

 

Advertisement