android - User registration verification with their device IMEI/ESN? -

I am working on an application that will validate users with their device IMEI / ESN number and all previous IMEI / ESN records if the user changes the device, is there a useful way I am already receiving the device IMEI / ESN, but how do I use it for user verification? Optional question: If this is not possible, how will I send 4 digit code (like viber) to user number after registering. Optional question: If this is not possible then how will I send 4 points / application? ? After registering in the application code on the user number (like viber)?

You can generate unique alpha-numeric strings from server side and map according to your requirement.

If you are using Java Server, the following code will help

  import java.util.Random; Public category RandomString {Private fixed last four [] symbols = new colors [36]; Fixed {for (int idx = 0; idx & lt; 10; ++ idx) symbol [idx] = (char) ('0' + idx); (Int idx = 10; idx & lt; 36; ++ idx) for symbol [idx] = (four) ('a' + idx-10); } Private Final Random Random = New Random (); Private finals four [] buf; Public randomthring (intangeline) {if (length & lt; 1) new invalid ungrounded exception ("length"; "+ length"); Buf = new four [length]; } Public string next string () {for (int idx = 0; idx & lt; buf.length; ++ idx) buf [idx] = symbols [random.nextInt (symbols.length)]; Returned new string (buf); }   
}  
}  
 and if you have a server language PHP then you MD%  
  md5 (uniqid (rand () However, the length of the input of the MD5 function is greater than the length of its output and confrontation is guaranteed so that the specificity is not guaranteed in that condition.  
 After that you need those keys and values ​​using a web service