PDF Encrypt / Decrypt
Add or remove a password on a PDF with AES-128 or AES-256 encryption.
PDF documents Heavy client-side (WASM) qpdf WASM from CDN
Tool preview
How to use it
- 01
Drop a PDF.
- 02
Choose encrypt or decrypt, then type the password.
- 03
Download the protected or unlocked file.
Limitations
- ! The encryption engine (qpdf compiled to WebAssembly, ~1.3 MB) is downloaded from a public CDN on first use.
- ! There is no password recovery: a forgotten password means the file is unreadable.
- ! Some readers ignore permissions flags; the password itself is what protects the content.
FAQ
What is the difference between the user and owner password?
The user password opens the file. The owner password controls permissions such as printing or copying; if you leave it blank, the user password is used.
Why does the first use download something?
The encryption engine is a WebAssembly build kept out of the page bundle so the site stays light. It runs locally — the PDF and the password never leave the tab.
Can I decrypt a file I do not know the password for?
No. This is real AES encryption, not an obfuscation trick.
Files never leave your device
Processing happens in your browser using the File API, WebAssembly and Web Workers. There is no upload endpoint.
Technical details
- Processing
- Heavy client-side (WASM)
- Implementation
- qpdf WASM from CDN
- Category
- PDF documents
- Network requests
- None while processing