Protect PDF
Lock a PDF with a password so it can’t be opened without it — strong AES encryption, free.
Drop your file hereTap to add your file
or click to choose · sent securely, deleted right after
Private by design. Your file is sent over an encrypted connection, processed in an isolated sandbox with no internet access, then deleted the instant it’s done. We never store it or read it. How this works
Protect PDF encrypts your document with a password. Once it is protected, the file can’t be opened, read or printed without the password you set — the contents are genuinely scrambled with AES encryption, not just hidden behind a prompt. It is the right way to secure anything sensitive you email or store.
Strong encryption needs a real crypto engine, so this is one of the few Ream tools that runs on a hardened server rather than in your browser. Your file travels over an encrypted HTTPS connection, is processed in an isolated sandbox, and is deleted immediately afterwards — nothing is kept. It is free, with no sign-up and no watermark.
How it works
Ream applies password encryption to your PDF and returns the locked file. From then on, every reader — Acrobat, Preview, your phone — asks for the password before it will open. Share the password separately from the file (a text or a call), never in the same email.
How to Protect PDF
Add your PDF
Drop the file onto the box above or click to browse.
Choose a password
Pick a strong password — a passphrase of several words is ideal.
Download the protected PDF
Click Run Protect PDF and save the encrypted file.
Choose a strong password
Your document is only as safe as the password on it. Use something long and hard to guess — a passphrase of several unrelated words is ideal — and store it somewhere safe. If you lose the password, the file can’t be recovered; that is the whole point of encryption. Always send the password to the recipient through a different channel than the file itself.
Encryption vs. watermarks vs. metadata
Password protection controls who can open the file. It is different from a watermark, which only labels a document, and from removing metadata, which clears hidden information before you share. For truly sensitive documents, protect the file and strip its metadata.
When to password-protect a PDF
- Emailing contracts, statements or invoices.
- Sending medical, legal or HR documents.
- Storing sensitive records where others might see them.
- Sharing a file that should reach one person only.
Why choose Ream
Strong AES encryption
The contents are genuinely scrambled — the file cannot be opened without the password.
Processed, then deleted
Sent over HTTPS, handled in an isolated sandbox, and deleted immediately after — nothing is stored.
Opens everywhere
The password prompt works in every PDF reader, on every device — no special software needed.
Free, no watermark
No account, no watermark, no limits.
Frequently asked questions
How do I password-protect a PDF?
Add the file, choose a password, and click Run Protect PDF. You download an encrypted copy that needs the password to open.
What encryption is used?
The PDF is encrypted with AES, so the contents are scrambled and can only be read with your password.
Is this processed in my browser?
No — strong encryption runs on a hardened server. Your file is sent over HTTPS, processed in isolation, and deleted immediately afterwards.
Can I recover the file if I forget the password?
No. There is no back door — that is what makes encryption secure. Store your password somewhere safe.
How do I remove the password later?
Use Unlock PDF with the password to strip it back off.
Can I protect a PDF without Acrobat?
Yes — no Acrobat and no install; it works from any browser on any operating system.
Is my file stored anywhere?
No. It is deleted immediately after processing — nothing is kept on the server.