Is it possible to restrict one subscription account to one device only?

I want to make a monthly subscription site. The problem is that people would then share their accounts with each other which would significantly reduce my profit. I just want to know whether it is possible to restrict one subscription to one device only? Or any other possible solution?

 

You could always store session ID and logout previous user if there is a new session.

 

Depending on what you have available, you could see if it's possible to use specific login-types (Facebook, for instance), or items using separate two-tier logins - although that would usually involve some sort of third-party / government issued / bank login type.

Barring those, you could store specific information identifying the browser/device used - create a complex string, and perhaps, if the string doesn't match, have a second tier that needs to be updated to allow the latest version to be stored, nullifying all the others (thereby only allowing one login) - for instance you could have a verification SMS sent to a registered number.

 

Sending a verification SMS is a very good idea indeed.

Would like to hear more solutions.