Different characteristic for every device.

[Epasta]

Dear all,

I have 10000 devices and I need to put a different value for every device, but I do not want to create 10000 firmware.

Is possible to do that with a tool? I must do that by firmware?

I must do this to identify every devices and to avoid that someone use my (Android and iOs app) with their button and not with mine.

Thanks to anyone

Best regards

[Hung Bui]

Hi Epasta, 

If possible could you let me know the purpose of having different characteristic (I assume different UUID?) unique to each device ?

I don't see how it can stop people from using your device ? 
One can simply clone their device using the same UUID as your device. And in the other way around can use their app and control your device, for example nRFConnect app. 

[Epasta]

Hi Hung Bui, 

before of all thanks for your reply.

The problem isn't people that are using my device with other app, the problem is that I don't want that people use my app (that cost around 50k euro per years) with a device that they can buy on Alibaba or Aliexpress.

I'll have a web server with all UUID, one time that you have connected your device, the app will go to check if UUID is on the web server.

If the UUID isn't present on the web server you can not use device with app.

If the UUID is present on the web server and another phone are using the same UUID you can not use the device with the app

If the UUID is present and free, you can use the device with the app.

I hope that everithing is clear

Thanks

Enrico

[Hung Bui]

Hi Enrico, 

I'm not sure how the device not from your company can operate the same as your device. However, cloning an UUID is quite simple. 
But yes, you can do what you plan by having a database and if a device already is in used it can't be reused. 
What you can do to have a random UUID is to use the DEVICEID value in the FICR of the chip as part of the UUID. It's a random generated value and should be "pseudo" unique to each chip. However you would need to have a database of all the DEVICEID. 

A better solution, in my opinion, is to use the Challenge-Response authentication. You can have a key stored on the device, the phone will send a random challenge to the device. The device would need to send a correct response back (by using the key to encrypt the random nonce) . If the app doesn't get a response or incorrect response, the app can disconnect. The checking can either be done on the app or on the web server. This way you don't need to have a database of all devices. 

[Epasta]

Hi Hung Bui.

before of all thanks for your reply and for your time.

I think that your idea is very good. In this afternood I'll go to propose that idea to my team.

You are the best as always

Thanks