Docly practical guide
PDF Encryption and Secure Sharing Guide
Password protection makes it harder for the wrong recipient to open a file, but it is only part of secure sharing. The complete approach combines three things: a strong password, a separate channel for delivering it, and permanent removal of anything that should not be in the document at all.
Password protect a PDF
Add the file and choose a long, hard-to-guess password. Avoid names, birth dates, account numbers or reference numbers that already appear inside the document, since those are exactly what someone would try first.
Test the password once after downloading the encrypted file. If you forget it, the document cannot be opened: unlocking requires the existing password and does not crack anything. Storing it in a password manager is safer than relying on being able to reach the person you sent it to.
How to deliver the password
Sending the file and its password in the same email is the equivalent of leaving the key in the lock. Anyone with access to that mailbox, or anyone the message is forwarded to by mistake, gets both at once.
Use a different channel for the password: a phone call, a message, or a corporate sharing system all work. If you are sending the same document to several people, a distinct password per recipient lets you identify the source if it ever leaks.
Encryption, redaction and watermarks
Encryption restricts access: an authorised recipient with the password sees the entire document. So if the file contains something a legitimate recipient should not see, encryption does not solve that problem at all.
Redaction removes the selected information from both the visible page and the underlying content, which makes it the right tool for identification numbers, account details and amounts. A watermark neither restricts access nor removes anything; it only states the document's status. These three should never be substituted for one another.
Checklist before sharing
Double-check the recipient address and which version you are attaching, since sending the wrong revision is a risk that no password protects against. If a PDF editor was used to draw black boxes over text, remember that this is not redaction and the text underneath is usually still selectable.
Review metadata such as the author name and revision history in the file properties. If you shared via a cloud link, close the link once the work is done; links left open indefinitely become the weakest part of the chain over time.
Quick checklist
- ✓Use a different strong password for each document.
- ✓Send the password through a separate channel.
- ✓Use permanent redaction instead of drawing a black box.
- ✓A forgotten password cannot be recovered, so store it safely.
Tools in this guide
Frequently asked questions
Can I open a PDF if I forgot its password?
Docly requires the existing password and does not crack forgotten passwords.
Does a black box delete hidden text?
Not necessarily. Underlying text may remain selectable, so use permanent redaction.