April 19, 2024

As irritating as it might be for an organization to lock you into its ecosystem by encrypting their protocols, you must admit that it presents an attractive problem. Cracking encryption might be extra bother than it’s price, although, particularly when a tool offers you all the tools you need to do an end-run around their encryption.

We’ll clarify. For [Valdez], the encrypted communication protocols between a DSC alarm panel and the management pads on the system have been severe impediments to integration into Dwelling Assistant. Whereas there are integrations obtainable for these alarm panels, they depend on third-party clouds, which signifies that not solely is your safety system probably telling one other laptop all of your juicy particulars, however there’s additionally the very actual risk that the cloud system can both break or be shut down; bear in mind the Chamberlain MyQ fiasco?

With these details in thoughts, [Valdez] got here up with a intelligent workaround to DSC encryption by specializing in bodily interfacing with the keypad. The system has a standard 16×2 LCD and a 25-key keypad, and a little bit poking round with a multimeter and a $20 logic analyzer ultimately confirmed that the LCD had an HD44780 controller, and revealed all of the strains wanted to decode the show with an ESP32. Subsequent up was interfacing with the keypad, which additionally concerned a little bit multimeter work to find out that the keys have been attached in a 5×5 matrix. Ten GPIOs on the ESP32 made it doable to just about push any key; nonetheless, the ten relays [Valdez] initially used to do the switching proved unwieldy. That led to an optocoupler design, sadly not as clicky however definitely extra compact and streamlined, and enabling full management over the alarm system from Dwelling Assistant.

We love this answer as a result of, as [Valdez] aptly factors out, the weakest level in any system is the place the place it will probably’t be encrypted. Data has to circulate between the person and the management panel, and by offering the digital equivalents to eyes and fingers, the underlying encryption is moot. Hats off to [Valdez] for a wonderful hack, and for sharing the wealth with the HA community.