Unity App Serial Activation 2

Simple job and my fix rate is not more than USD40 Would like to create a serial number activation for my apps created using unity - First when user open apps that i build using unity, it will show a textboxt and submit for them inserting the serial number of the product. The serial number will be printed on the product box when the customer buy my product. - Once entered and submitted it will check the serial key using java,php if it valid from the mysql database. The activation number already in my sql database. Just need to activate it. - If the key is valid it will start the program . - For validated customer the textbox field should not be shown again. The apps should open the apps without activation directly. The activation will be one time only in the phone. - For the serial key it is limited to be registered for 5 times only. Let me know in the code where i can change the number also. - The activation form should show normal alert for validate on empty, validate on invalid key, validate when the registered key reach the limit with showing my contact info for support