Encrypt a PDF with AES-256 and a password of your choice. Optionally block copying and printing.
With HelpRange only the people you choose can open the document (one-time code to their e-mail), downloads can be blocked, access expires or is revoked – and you see who opened it and which pages they read.
Password protection keeps a PDF unreadable without the password – useful when a file has to travel as an attachment. Its weak point is the password itself: it is often sent in the next e-mail and forwarded together with the file. For confidential documents, a link that verifies the reader's e-mail and can be revoked is safer.
AES-256 – the standard used by Adobe Acrobat. Use a password of 10+ characters.
No. Both are used in memory to create the encrypted file and are not kept.
Never in the same e-mail as the PDF – use a phone call or a messenger. Or share a link that only the recipient's e-mail can open.