On July 30th, a rather curious posting was made on United TI, a forum devoted to discussing Texas Instruments graphing calculators. The post, made by Benjamin Moody — known as “FloppusMaximus” on the site — gave the factors of a very large number. It was quickly deduced to be the RSA modulus of a key — particularly, one needed to sign the OS on a TI calculator — which Moody confirmed:
This one is for the TI-83+.
The TI-83+, like all modern TI calculators, has its OS cryptographically signed by TI for validation purposes; if someone tries to upload an unsigned OS — like, say, an open-source OS — into the calculator, it is rejected. Thus, the discovery of the signing key is a major breakthrough, which ticalc.org, a popular TI calculator site, makes clear:
With this achievement, any operating system can be cryptographically signed in a manner identical to that of the original TI-OS. Third party operating systems can thus be loaded on any 83+ calculators without the use of any extra software…Complete programming freedom has finally been achieved on the TI-83 Plus!
A few days ago, however, the original post was removed and replaced with this:
Dear community,
I have been politely asked to remove the former contents of this post.
No further explanation was given by Moody as to who asked him to remove the key or why it had to be removed. However, Brandon Wilson, a developer who reposted the key on his website, explained:
Ben was hit by TI with a DMCA notice as was I. We of course must comply with whatever is specifically requested, but you can’t stop a group of people from factoring large integers. I will not be silenced.
Wilson has posted the DMCA notice and his reply on his website. Meanwhile, a distributed computing project has been set up to use Moody’s brute-force methods to obtain the keys for all other TI calculators.
It seems pretty clear to me that TI is abusing the DMCA to maintain a stranglehold on their hardware. The key in question does not encrypt the OS, so it’s unclear how the key counts as a device to circumvent access controls on copyrighted works. You don’t need it to obtain a copy of the OS, as copies of the latest OS are freely downloadable on TI’s website. The only thing the keys are useful for is to be able to upload another OS onto the calculator such that it can be installed. One poster on the United TI forum drew parallels between this situation and the situation with iTunesDB, and I think that’s a valid point to make.
TI is not trying to protect their copyright, but merely trying to protect their lockdown on their hardware. If TI is really interested in promoting the education of young people, they should stop trying to harrass others whose only crime was to explore what they could do with the hardware they legally purchased.










