TI-83 Plus OS Signing Key Cracked

Posted by Michael on 31 July 2009, 15:33 GMT

The ever-mysterious Benjamin Moody posted a cryptic message on the United-TI forum yesterday. In it, he listed the factorization of the 512-bit RSA modulus used by TI's OS signing key for the 83+ (the "0004 key"). No other details are yet available about how he achieved this feat of substantial brute forcing power. In the event of United-TI downtime, Brandon Wilson has put a copy of Benjamin's values on his personal website.

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 (that was mentioned in recent news) Complete programming freedom has finally been achieved on the TI-83 Plus!

Update: Benjamin has posted additional details on the United-TI forum thread.

Update: A distributed computing project has been set up. Information about how to join the effort to crack the OS keys for the remaining TI models can be found here.