Email is not private, shared drives get shared further than intended and USB sticks get lost. Putting a password on a sensitive PDF means that anyone who gets the file without the password sees nothing useful. Done right, it takes a minute.
Two kinds of password
A PDF can have an open password, also called a user password, which is needed to open and read the file. It can also have an owner password and permissions, which are flags saying whether printing, copying text or editing is allowed. The two are not equally strong. The open password encrypts the content. Permissions are instructions that well-behaved PDF apps respect, but they are not a lock. If it matters, rely on the open password.
Protect a PDF in DocPro
- Open Protect PDF and choose your file.
- Enter the password people will need to open it. Use the Show passwords option to check you typed it right.
- Optionally set an owner password and choose permissions such as printing or copying.
- Optionally also encrypt the metadata.
- Save the protected PDF. It uses AES-256 encryption, and everything happens in your browser, so neither the file nor the password is uploaded.
Protect PDF is a Pro tool on the web. You can set it up without an account; the final save asks you to sign in to DocPro Pro.
Choose a good password
- Length beats cleverness. A passphrase of four or five unrelated words is easier to remember and harder to guess than a short string of symbols.
- Do not reuse the password of your email or bank.
- Avoid obvious choices: names, birthdays, “password”, or the file name.
- Use a password manager to generate and store it if you can.
Share the password separately
If you email the protected PDF and the password in the same message, the protection is gone. Send the password by another route: a text message, a phone call or a messaging app. Tell the recipient which file it belongs to.
Do not lose the password
DocPro never stores your password, so it cannot be recovered. If you forget it, you cannot open the file. Keep the unprotected original somewhere safe, or write the password down in a secure place. If you forget the owner password you cannot change the permissions later either. Leave it blank and a random one is used, which nobody knows.
Order of operations
Do your editing first. Protected files cannot be modified until they are unlocked. A good order is: fill in and sign, then compress if needed, then clean metadata, then protect last. If you need to change a protected file, use Unlock PDF with the password you know, edit the copy, and protect it again.
Passwords on a phone
The steps are the same on a phone, and phone PDF viewers all ask for the password when you open the file. If you use a password manager on the phone, create the password there, copy it into the tool, and store the entry with a note saying which file it belongs to. Doing this before you send the file avoids the common mistake of choosing something quick and then forgetting it.
Test it
Open the protected file in a different app or on another device. It should ask for the password. Try the wrong one to see it fail, then the right one. Check that printing and copying behave as you chose.
What a password does not do
- It does not stop the recipient from sharing the file and the password.
- It does not hide the file name. Name it neutrally.
- It does not protect a copy that exists elsewhere unprotected, such as in your downloads folder or an email you sent earlier.
- It does not remove personal details stored in the document properties unless you also encrypt or clean the metadata.
A password is a lock, not a safe. It is a very good lock if the password is strong and kept secret.
For most personal and business documents, an open password with AES-256 and a good passphrase is the right level of protection.