Help on how to block unauthorized distribution of excel sheet

[Raspotin]

Hi Guys

I'll explain my problem to better understand, so you can recommend the best approach to fix this problem.

Sometimes a I deal with the sale of some analysis excel files that I created.
What I need is a method to keep them from being spread or shared by customers, as many represent months and months of work and are also sought after enough to save a lot of time and effort.
Once purchased, I would like the customer to have the opportunity to see the formulas, also modify them, but that they cannot in any way send them to other people or even worse resell them as has already happened.

How can I ensure that only the customer who bought them can use them? and if the sends are inaccessible by those who have not been verified by me?
for example, would it be possible to create a macro in which I insert the buyer's email so as to allow him access only with the email I added?
or a macro in which I create a disposable password vocabulary, of which I give a password to the customer and once used it is no longer reusable a bit like the coupon codes,
But by doing so perhaps you will totally unlock the file and could easily share it ....

and I wanted to get your advice on how you could go about fixing this in any way you think will work

I don't know guys I am very lost and confused and I don't really know how to proceed, I would be really very grateful for your help,on some advices on solution
since I don't even know what is feasible and what is not ..



Thank you very much and have a nice day !

 

[Oaktree]

Honestly, my advice is to consult with a contract/intellectual property lawyer instead of the Excel board. You are better off putting the right legal phrasing into the contract you have them sign than you are trying to hold your files hostage. You should assume that any type of security you try to put into Excel could be hacked (and not by a ninja level hacker... but by anyone who Googles "hack VBA password" and pays $40).

Would you know if they sold your file? Probably not. But, knowing that they could be sued for forever amounts of money if someone they sold it to were to tell you about it is usually enough of a deterrent.