ESP8266 Community Forum

- Tue Jan 19, 2016 6:43 am #39216 Hi

I'm working on a project to uniquely identify an ESP8266 using statistics over time. Hence I need as much out of the ESP as possible that varies from device to device, location to location, power supply to power supply etc..

Useful starters are RSSI, ADC (noise), RTC calibration and of course fixed items such as device ID, Host ID, MAC address.

The fixed items are however not so useful. I'm looking for more items which will vary whenever they are read and may change due to circumstance. I thought some register values to do with the WIFI radio might be useful but such info is very sparse in the API.

Any ideas, or sources of info? I'm programming in C using the Eclipse Windows environment... I can't assume the presence of anything other than the Expressif libraries... so registers and any memory locations that are guaranteed unused but may vary on power up??

Any help appreciated.

Pete.

Peter Scargill - http://tech.scargill.net

- Tue Jan 19, 2016 12:13 pm #39241 I don't get what you are trying to achieve...
The MAC adress is guaranteed to be unique. So if you want to identify an ESP, use the MAC and you are done.
Why would you mess around with (potentially unreliable) statistics when there already is a unique identifier?

- Tue Jan 19, 2016 12:22 pm #39244

The MAC adress is guaranteed to be unique. So if you want to identify an ESP, use the MAC and you are done.

The MAC-address is just derived from the chipID, which is always unique. If one wants a unique identifier they could just use ESP.getChipId(), no need to mess with MAC-address for that.

- Tue Jan 19, 2016 12:27 pm #39245 Thanks both - and thanks for the comment about MAC ID and Chip ID - that means one of them is reduntant.

Why mess around with potentially unreliable info - simple really - the MAC is easy to clone. I need to SECURELY identify the unit by analysing it's characteristics. That includes a random number. Well, I already found that out - and by the look of it a damned good random number. But I also need things which are unique to that board. Looked at over time the RTC clock jitter will be unique, affected by voltage and temperature. I wanted to read the voltage but you have to have TOUT disconnected for that and I want to do this analysis on existing boards where TOUT may well be used. Is anyone aware of a source of information on the radio chip and it's registers and other registers where their change may be affected uniquelly?

Peter Scargill - http://tech.scargill.net