Question: PDF password protection not working in Preview with OS X 10.13
Have upgraded my MacBook Air to OS X 10.13.2 and have noticed that ever since I upgraded to High Sierra, the password protection in Preview does not seem to work. Under previous OS X releases, when I set a password to protect a PDF's contents against copying, it would work, i.e., when I try copying text or images from a file that I just protected, it would ask me for a password.
But ever since I upgraded to High Sierra, I am able to open a PDF that I had just password protected, then copy any content without being asked for a password. Has anybody else experienced this? Am concerned since we use Preview to digitally-sign documents, so if there is a vulnerability in OS X 10.13, this puts us at risk.
Hope someone can shed light on how to ensure the integrity of digitally-signed PDFs created in Preview without resorting to buying additional software subscriptions. Thanks in advance!
MacBook Air, OS X Mountain Lion