Make a program with a MID protection against copy

[Anonimo]

I’ve used SlimLine PLC’s previously, now I’m working in a new project where I’m thinking in using your products again, but for this application I need to use the MID protection, for me all this is new.

Although I’ve already been looking at the forum its still not clear how to proceed, my concern is related with the program protection. We want to avoid the possibility of the program being copied to another PLC and run without our consent. From what I’ve read I think the MID will do just that, anyone can copy or backup the software but then it won’t run in an hardware without the proper MID. Right ?

In this project I don’t need to use any of the special FBs at your webpage, but I take this opportunity to ask of its possible to create my own FB’s and protect them leaving the rest of the program code visible (Can this be done also ? Involved cost ?).

[Sergio Bertana]

The MID, is a code that can be written only by Elsist, we can assign a MID code to a customer and write it on the products the customer buys. A special function allows the customer to check by program if the product has the proper MID or not, so by checking it on own programs, functions or FBs it’s possible to stop them if the MID doesn’t match.

With the MID code you can develop programs, functions or FBs that can be run only on a products that have the proper MID written on. So anyone can copy or backup the software but it doesn’t be run in an hardware tha hasn’t the proper MID.

Your FBs can be protected by checking the MID by code on them, and obviously the source code of these FBs must be encrypted (Like ours) otherwise anyone can modify the code to bypass the MID control. To encrypt an object, choose from the Logic Lab the object, with the mouse right button menu, select encrypt (See screenshot), and then set a password (a unique password for all the objects or separate password for any object).

[Anonimo]

Supposing I have to develop a software for a customer that would like protect the final application against copies, can he buy the MID ? If yes I have to check the customer MID in the software I develop, can I know the customer’s MID ?

The customer pays for the software development and I have to supply the source so he can reuse it in different applications. Now the question is, supposing to use in the source some parts of code that I would like protect is it possible to protect only these parts ?

[Sergio Bertana]

Yes the customer can buy the MID directly, we will register the code to him and only the products we sell to him can have its MID programmed on. The MID code is not secret, it can be directly seen on the web page (See screenshot), secret (Crypt) is the part of code that checks it.

If you would like to protect some parts of your own code, you have to write functions or FBs and encrypt them with your own password. So you can use them inside the code you develop for the customer. A good practise is to include all of them inside a library you supply to the customer.

[Autore]

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