PDF Security & Signing Tools
PDF Security is for controlling who can open a document, what it reveals, and what has been done to it. Add a password before you email a contract, remove one from a file you are allowed to open, black out names or account numbers for good, strip the hidden author and software details, or turn a filled form into a fixed record. Sign PDF places your signature on a document you control, and Add Watermark stamps text such as CONFIDENTIAL across the pages.
Because these tools handle sensitive files, how they work matters. Every one runs inside your browser, so the document and any password you type are never sent to a SmilingPDF server. Redaction rebuilds the page so the covered text can't be recovered, rather than just drawing a black box over it.
Protect, redact, sign and clean up
Protect PDF
Add a password to lock and encrypt your PDF
Unlock PDF
Remove password protection from a PDF
Redact PDF
Permanently black out sensitive text
Sign PDF
Draw, type, or upload a signature with audit trail
Flatten PDF
Bake a filled form's values into the page, permanently
Add Watermark
Add text or image watermarks
PDF Metadata Editor
View and edit title, author, subject and keywords
Remove PDF Metadata
Strip every hidden property from a PDF in one click
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FAQ
Frequently asked questions
Got questions? We've got answers.
Is password protection real encryption?
Yes. Password Protect PDF uses the PDF Standard Security Handler with 128-bit RC4 encryption, which Adobe Acrobat, Preview and most other viewers support. RC4 is older than the AES encryption some tools use, so it suits keeping a file private in transit better than guarding highly sensitive data.
Does redaction really remove the text?
Yes. Redact PDF rebuilds each page as an image with the boxes burned in, so the covered text is gone from the file instead of merely hidden underneath. Nothing is redacted until you click Apply.
Can I unlock any PDF?
Unlock PDF removes the password from a document you are allowed to open, and it also clears restrictions on copying and printing. If a file needs a password just to open, you have to supply it.
Are my documents and passwords uploaded when I use these tools?
No. Every tool here runs in your browser, so the file is processed on your device and is never sent to a SmilingPDF server. Only anonymous usage counts — which tool was used, never what was in it — leave the page.