Protect PDF with Password (AES-256)
Lock your PDF document with a secure password and AES-256 encryption.
How it works step by step
- 01Select the PDF document you want to secure against unauthorized access.
- 02Enter and confirm a strong password to lock the document.
- 03Click Protect and download your AES-256 encrypted PDF.
Technical specs & privacy
True military-grade AES-256 encryption
Complies with standard PDF Security Handler (V5/R6) specifications.
Password never travels over the network
Unlike cloud tools that transmit your passphrase to their servers, our encryption runs 100% locally in your browser.
Universal compatibility
Your protected PDF opens reliably in Adobe Acrobat, all major browsers, iOS, and Android.
| Supported input formats | PDF FILE |
|---|---|
| Output target format | PROTECTED PDF (AES-256) |
| Conversion engine | pdf-lib & PDF.js 2x Canvas (in-browser local) |
| Storage & Privacy | 100% Local · Files never leave your device |
Frequently asked questions
Is my password sent to any remote server?
Never. AES-256 encryption is computed inside your local browser via native WebCrypto. Nobody else ever sees your password or document.
Which encryption algorithm is used?
We use official AES-256 (V=5, R=6) standard security specified by ISO 32000.
Can you recover a lost password?
No. Because AES-256 is mathematically secure and we store nothing, be sure to keep your password in a safe place.
Does the protected file open on mobile phones?
Yes. Every modern PDF viewer on iOS, Android, macOS, and Windows supports password prompts.
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