This method does not provide 100% protection from direct copying. It was not designed to replace regular protection mechanisms, like encryption, steganography, etc. Rather it was designed first of all for supply chain applications or for any other application that utilizes barcode as “information tag” and "protection" would be a supplemental requirement.
However, since one of the “Protection Keys” is an arbitrary alphanumeric number (Serial Number, Batch Number, Tracking Number, etc.) that can be changed at any time, it makes the task of counterfeiting and copying symbols very difficult, or expensive, or both.
If you want to use it for protecting documents just from tampering it’s more complicated. Theoretically, it’s similar to the situation that you would protect your document with digital signature, but the key-exchange protocol was broken by an intruder. If it happens, the intruder can tamper the document, sign it with your digital signature and receiving party will never recognize that it is a fake.
We have designed “Product ID” option having this particular problem in mind. Since you can change it at any time, you can protect each document with any (different) “Product ID” and you are free to change it as often as you want. So, unless the intruder intercepts all your communications you will be able, at least, to nail him down pretty quickly.
Within the next few months we will start offering a new latentogram-based tamper-proof protection label used in combination with our Protection Suite – this will resolve document protection issue, in general.