A client of ours wanted to know if they could remove the password from a document (that was in a portable format) and change it’s content. We replied that it would be difficult to do so and that it could destroy the format (to discourage them). However at the end of the day they came back with the solution by themselves. They downloaded a free software and removed
the password. The document was an invoice, they wanted to increase the expense amount.

As for encrypted documents and protection levels, it all depends on the algorithm being used. The digital document may be well protected but secret services or even hackers may find a way to decrypt any document.

Personally I do not believe that digital documents are more secure than physical ones.

I just remembered a case back in the MS-DOS era, about a company that had a single computer hosting the accounting software system. It wasn’t even connected to the LAN! It was locked inside a room and only a designated person had access to it under a strict policy. It seemed like the optimum protection but just imagine the gap of information that this caused due to lack of exchanging information within the company.

I once developed an application for an organization that was collecting
information. They had two networks one for the internet and one for their database system. There was no physical connection between the two networks, I guess you can understand why. Wouldn’t it be nice to be able to embed metadata in a biological or quantum state inside a document?

Disclaimer: We are against stealing other people’s intellectual property.