Excel Software “Licensing”

Hey guys, about a year ago my company created an estimating program in excel. They have began consulting other firms and would like give this software to them as part of their acceptance package.

My question is, my boss recently asked me if it would be possible to “license” the software so that after a year or so the program would cut off and require a new password for entry. If our client were to re-up their contract, we would provide them with the new password.

Is this feasible to do in Excel? The program is primarily in VBcode, so I’m wondering if something could be added to create this. Any help is appreciated