Many thanks, Aditya.
Unfortunately, the link to the video is not working, but I should be able to
find another route.
If I am correct, you first secure the document with a password - presumably,
they need this password to open the file? Will this interfere with the
If you are using Certificate Security then no, you do not use a password to first secure the document.
There are two parts to the document security story; file access and file permissions. Whether you use Password Security or Certificate Security the same two concepts apply. The first part, file access, is pretty straight forward. You lock the document using a security method and only the individuals that have the key can open the file. With Password Security the Document Open Password is the key, and if you know it you can open the document, if not you can't. With Certificate Security it's having access to digital ID that is associated with the public key that you used to encrypt the document. If you have access to the digital ID (really the corresponding private key which is wrapped into the digital ID) you can open the file, and if you don't you can't.
Once the file is opened comes the permissions part of the equation. As the document author (really the person that is encrypting the document) you have the capability to enforce a set of permission that give the recipients of the document certain rights. For instance, you can either allow or deny the ability to print the file. If you really don't want to allow someone to get their unauthorized hands on the file disabling printing is a good step. The thing is, once the file is printed all someone has to do is scan the pages and car build a representation of the original document. If they can't print in the first place they can't circumvent the security. another thing you can do is prevent (disallow) editing of the document. That way the recipient cannot remove the watermark.
Is any of this fool proof, no. The recipient could use their camera phone to take a picture of each page on the screen and rebuild the file that way. It wouldn't look very good, but if they are hell-bent on breaking confidentiality then there are ways, it's just that you want to make it as hard as possible for them.
Many thanks for that, very helpful and really appreciated