Unlock PDF vs. Protect PDF
Removing a PDF's password vs. adding one — opposite operations.
PDF Tools
These are inverse operations on the same underlying encryption. Unlock PDF removes password protection and any permission restrictions from a PDF you can already open (you need the password to use it). Protect PDF adds AES-256 password encryption to a PDF that doesn't have any yet.
Unlock PDF
Best for
- Removing a password from a PDF you have permission to open
- Removing permission restrictions (like disabled printing) along with the password
Trade-offs
- Requires knowing the existing password — it can't recover or bypass one you don't know
Protect PDF
Best for
- Adding password protection to a PDF before sharing it
- Securing a sensitive document with AES-256 encryption
Trade-offs
- Can't protect a PDF that's already encrypted — unlock it first if you need to change its password
| Dimension | Unlock PDF | Protect PDF |
|---|---|---|
| What it does | Removes encryption | Adds encryption |
| Requires | The existing password | A new password you choose |
| Encryption | N/A — removes it | AES-256 |
Verdict
These aren't really alternatives to choose between — you'll use whichever one matches the direction you need to go: Unlock to remove a password, Protect to add one.