Add a strong password to a PDF so only the people you share it with can open it. PDF Cubby uses genuine AES-256 encryption — the same standard trusted for sensitive documents. Set your password, download the locked file, and nothing is kept afterward.
How to password protect
Add your PDFChoose the PDF you want to lock.
Set a passwordEnter the password that will be required to open the file.
EncryptApply real AES-256 encryption to the document.
DownloadDownload the protected PDF. It's gone from our side the instant you do.
What you can do
- Lock bank or tax statements before emailing them
- Protect medical or legal paperwork
- Secure payroll or HR documents
- Add a password to a contract before sharing
- Keep personal records private in shared storage
What happens to your file
Your files are never stored. Nothing is parked, queued, or kept — the moment your download is ready, it's gone, and no one ever sees it.
Plenty of online tools store your file on their servers and delete it later. PDF Cubby doesn't keep it at all — there's nothing left behind to clean up afterward.
Features
- Genuine AES-256 encryption, not a fake lock
- Open password so only the right people can view it
- Works on already-restricted files too
- 5 free a day — unlimited with Pro ($4.99/mo, cancel anytime)
- Never stored — nothing kept afterward
Tips
- Use a password you'll remember — a locked PDF can't be opened without it.
- Share the password over a different channel than the file itself.
- Redacting sensitive content too? Do it first with Secure Redact, then lock.
Frequently asked questions
- Are my files kept after protecting them?
- No. Your PDF is never stored — the instant your locked file is ready, everything is gone and no one sees it.
- What encryption is used?
- Real AES-256 — a strong, widely trusted standard. The password is genuinely required to open the file; it isn't a cosmetic lock.
- What happens if I forget the password?
- There's no back door — a correctly encrypted PDF can't be opened without its password. Store it somewhere safe.
- Can I lock a file that's already restricted?
- Yes. Files with existing restrictions are handled and re-locked with your new password.
- Will it open everywhere?
- Yes — any standard PDF reader will prompt for the password and open it once entered.
- Do I need an account?
- You get 5 free uses a day with no account. For unlimited use, sign in and upgrade to Pro — $4.99/month, cancel anytime. The 6 core tools (merge, split, extract, rotate, compress, convert) are always free and unlimited.
- Is my original changed?
- Never — you download a new protected file and the source stays intact.