Document protection

[Woody44]

I am working on a project that will result in a book of prints of computer (CADD) drawings. The original drawings are on several different size sheets (pages); the book will be formatted for pages in the U.S. ledger size (11" x 17", or 279mm x 432mm).

The print-on-demand publishing services such as Amazon KDP and Ingram-Spark don't offer pages that large. I can find custom printers who will produce the book, but they are printers -- they would print a batch of books and ship them to me in a box. I would prefer not to be involved in storing, packing, and shipping books on a one-at-a-time basis.

An alternative would be to offer the book in the form of a PDF, but I'm concerned that it would be too easy for a person to buy one copy and then give copies to all their friends. I know that FlexiPDF allows setting a password to provide protection against unauthorized editing or printing, but is there any way to limit or prevent unauthorized redistribution of the file itself?

[Michael Uplawski]

An alternative would be to offer the book in the form of a PDF, but I'm concerned that it would be too easy for a person to buy one copy and then give copies to all their friends. I know that FlexiPDF allows setting a password to provide protection against unauthorized editing or printing, but is there any way to limit or prevent unauthorized redistribution of the file itself?

I like the problem, but am afraid that any solution will complicate the relation between you and your readers.

When I isolate the situation of the PDF reading customer, you have one person who has access to the content of the file.
Giving the file to someone else should not give access to that person. Many ways exist to achieve this. The question is, how will the new reader finally get access?

The only way that I can imagine is by use of asymmetrical cryptography. As your needs are very specific, the concept must be, too. Currently available software is technically able to do what you want, but I cannot see an easy way to establish the necessary communication between you and the potential customer, nor how the somewhat enormous administrative work can be diminished.

My answer for the time: No.

[Jossi]

An idea that is not 100% safe, but relatively easy to handle: If you put a note in front of every (read-only) PDF which says: ‘This PDF was licensed for XY [name + email address + date]’, you don't prevent it from being passed on to individual friends, but you do create a fairly high psychological barrier to resale or unrestricted distribution via torrents or similar. I know at least one Swiss publishing house to protect their epubs this way (without further DRM measures).