Getting global device ID?

Question

Iron

The device can be:
- a smartphone with Android;
- computer with Windows, Linux.
Which parameter (option set, option set hash) is best to use as a global identifier? How does it look like in C#/Java?

Answer 1

It is possible to generate a UUID . In fact, the probability of the same identifier on multiple devices is close to zero.
Apple, for example, uses UUIDs to generate identifiers for their products:

Answer 2

when you first start your application, generate a large random number (128bit for example), you need to remember it. The probability that on some other device (in the presence of straight arms) the same number will be generated is almost zero. This number is used as an identifier. Versatile, simple, reliable.