What was the result of analyzing the code that emerged from hacking an electric toothbrush?

Some commercially available electric toothbrushes have a feature that recognizes when the brush head is attached and notifies you when it's time to replace it. Engineer

Aaron Christopher hacked an electric toothbrush in an attempt to unlock this password-protected feature.

Hacking the Philips Sonicare NFC Password - YouTube

The Philips Sonicare electric toothbrush has a function that communicates between the brush head and the handle, and notifies the user when it is time to replace the head when it gets old. This function is password protected, and it is possible to unlock the function and freely change the brush head usage time using special equipment or software, but Christopher is trying to realize this by analyzing the algorithm for calculating the password and unlocking the function change.

To hack the electric toothbrush, Christopher bought an NFC-enabled Sonicare for 40 euros (about 6,700 yen) and immediately began disassembling it.

Examining the board reveals that it is equipped with an NFC reader 'MFRC630', a MindMotion 'MM32F001 Cortex M0' SoC, 16KB of flash memory, 2KB of RAM, and the debug pins are clearly labeled.

When I connected the board to a PC and the flasher, the information on the SoC, RAM, etc. was displayed without any problems. In addition, a mysterious code '28 06 00 20 C9 00 00 08' was also detected.

Using the program analysis tool IDA, the code was found to be the NFC password used on the brush head and the electric toothbrush itself. 'The code is in the user identifier in the NFC tag, and we were able to easily analyze it by looking at the manufacturing string printed on the brush head,' Christopher said.

Christopher has published the NFC password he discovered on GitHub.

Philips Sonicare NFC Password generation · GitHub

Christopher revealed that he was inspired to try hacking a toothbrush after fellow engineer Cyril Kunj hacked a Philips Sonicare electric toothbrush.

Hacking the brush head of an electric toothbrush can rewrite the usage time - GIGAZINE

in Software,   Hardware, Posted by log1r_ut