Security control of users by checking the code (IMEI or whatever) of users' mobil phone (android).

We have mobile VR (virtual reality) apps downloadable google play. Only subscribers can open our apps. Our purpose: After a subscriber downloaded our app to his/her mobile phone, he can not use any other mobile device to open that app anymore. To check if a subscriber always using the same mobile phone, our method is: 1.) A user will come to our website (we have a website) and record his/her information on a form by using his/her phone! 2.) This information will go to a database (on our hosting company). Also, during this operation, the code (IMEI or whatever) of users' mobil phone (android) will be get automatically and will go to our database! 3.) When user pay the subscribe-payment, we will give an OK to user on a panel of database. 4.) Whenever a subscriber want to open our app, a new app have been put in the front of our app must check if the payment is OK and the code of phone is OK. There are two work must be done: 1.) A database must be prepared to cover required information, with a form at our web site and with a panel we use to see the subscribers information. 2.) A mobile app to check the phone and to check the required information from database. Please write us for your questions. Thank you.