Is browser-based PDF encryption safe?

Yes for the encryption algorithm itself — OmniPDF uses standard AES. Safety comes down to the password you choose. Use a long, unique password and store it in a password manager.

Can OmniPDF crack a password I don't know?

No. Only known passwords can unlock a PDF. OmniPDF does not brute force passwords and cannot bypass ownership restrictions.

Is a signature from OmniPDF legally binding?

Many contracts accept simple electronic signatures. For high-value or regulated agreements, use a qualified digital signature from a certificate authority.

PDF security tools

Protect, unlock, watermark, redact and sign PDF files. Eleven tools for controlling who can open, edit or share a document — all running locally with AES encryption and pdf-lib drawing primitives.

Tools in this category

What security tools do and don't do

The tools in this category handle three different jobs, and it's important to know which one you need:

Encryption — makes the PDF unreadable without the password. This is real, mathematical protection. Use Protect PDF, Encrypt PDF or Change PDF Permissions.
Visual markers — watermarks, signatures and highlight overlays. These do not prevent anyone from reading the document; they just add visible content. Use Add Watermark or Sign PDF.
Content removal — redaction removes visible text and replaces it with a black box. Only the rasterized redaction in Redact PDF actually removes the underlying text; adding a shape does not.

Password protection honestly explained

Protect PDF uses standard AES encryption. This is the same encryption used by desktop PDF software. The security depends on the strength of your password, not on the tool. A four-character password can be cracked in seconds; a twenty-character random password cannot be cracked with current hardware. Use the PDF Password Generator for a strong one, and store it in a password manager.

Unlocking PDFs you own

Unlock PDF removes a password from a PDF when you already know it. This is useful when you receive a file from a colleague, save the password, and want to remove it later. OmniPDF does not crack unknown passwords and cannot bypass ownership restrictions on files you do not own.

Redaction that actually works

Adding a black rectangle on top of text is not redaction — the text is still in the file and can be selected, copied or extracted. OmniPDF's Redact PDF actually removes the text by rasterizing the page after drawing the box. The resulting PDF has no underlying text behind the redacted area.

Electronic vs digital signatures

The Sign PDF tool places an electronic signature image on the page. It is a visual signature, legally valid for many contracts, but not a certified digital signature. For regulated agreements, use a qualified signature service such as DocuSign, Adobe Sign or your national eID provider.

Privacy

All encryption, decryption, watermarking, redaction and signing happen in your browser. Passwords and signature images never leave your device. This is safe for the most sensitive documents.