The power of Bitcoin is giving your dusty old TI-89 calculator a second chance of being useful.Matt Whitlock, who helped make one of the world's first Bitcoin ATMs, is at it again. In a video posted on to Vimeo, he showed how using the calculator once only used for high school geometry and a 12-sided die makes a secure address for your Bitcoin account.The video self-explanatory. Load up your calculator with the code, roll it 72 times and enter the number rolled into it. After that, the calculator pumps out a private key and address.We've reached out to Whitlock to see what the purpose of this is, but someone on Reddit might have already pointed out the obvious factor: it's secure because it never connects with a "NSA backdoored" computer when generating it.