Security · PDF tools
Password Protect PDF — Free Online Tool
Lock PDFs with AES-256 — the same encryption banks use.
About Password Protect PDF
Locking a sensitive PDF is one of the most-misunderstood security operations on the internet. Plenty of free tools claim password protection but quietly use RC4 40-bit, which a basic laptop can crack in minutes. Others embed the password inside the PDF in plaintext. Our tool uses QPDF to apply true 256-bit AES encryption — the AES standard ratified by NIST, the same cipher used by banks, governments, and the entire HTTPS web. Two password tiers are supported. An open password (user password) prevents anyone without it from opening the document. A permissions password (owner password) allows opening but restricts printing, copying text, editing annotations, filling forms, or extracting pages. You can set either independently, or both. The encryption is performed in a temp directory that wipes itself in two hours, and the unencrypted upload is shredded immediately after the encrypted output is built. We never log the password — once you set it and download the file, the password exists only in your head and inside the file. Lose it and even we cannot help you recover the contents.
How it works
Upload the PDF you want to protect.
Enter an open password (required) and/or a permissions password (optional).
Choose which permissions to restrict.
Click Protect and download. The encrypted PDF is yours; the original is wiped.
Why use our password protect pdf
- 256-bit AES encryption (PDF 2.0 standard)
- Independent open-password and permissions-password tiers
- Per-permission flags: print, copy text, edit, fill forms, extract pages
- We never log the password — set-and-forget
- Compatible with every modern PDF reader (Acrobat, Preview, Edge, Chrome)
- Original file shredded after encryption completes
Backed by QPDF with AES-256 encryption — PDF 2.0 spec compliant.
Common use cases
- •Email confidential client reports without third-party file-transfer software
- •Protect tax returns and financial statements before sending to a CPA
- •Encrypt medical records for HIPAA-compliant transmission
- •Lock employment contracts so they cannot be edited after signing
- •Protect intellectual property like prototypes, designs, and patent drafts
- •Add a second factor when sending a sensitive PDF over Slack or Teams
File size limits and privacy
Up to 200 MB free / 2 GB Pro. Input: PDF. Output: PDF (encrypted).
All files are sandboxed in temporary directories, scanned by ClamAV before processing, and auto-deleted within two hours. The download card includes a Delete File Now button for immediate purge. Read the full security and privacy documentation →
Frequently asked questions
What encryption strength is used?
256-bit AES — the strongest cipher supported by the PDF 2.0 spec and the same standard used in HTTPS, banking, and government communications.
Can you recover my password if I forget it?
No. We never see the password — it is hashed into the encryption key on your file and we keep no record. If you lose it, the file is unrecoverable. Use a password manager.
What is the difference between open and permissions passwords?
Open password (user password) is required to view the file. Permissions password (owner password) allows viewing but restricts actions like printing or copying text. You can set just one or both.
Does encryption survive PDF processing in other apps?
Yes. Encryption is part of the PDF structure itself, so it remains in effect whether the file is opened in Acrobat, Preview, a browser, or a mobile reader.
Can I bulk-protect multiple files?
Yes. Pro users can apply the same password to up to 20 PDFs at once. Each file gets its own encrypted copy.
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Ready to password protect pdf?
Launch the interactive tool — no signup, no install, no watermark on the output.
Open the Password Protect PDF tool →