PDF Security Tools

Password protect, sign and redact PDF files

PDFs often carry contracts, invoices, medical records and other details that should only reach the right people. PDF security comes down to three questions: who can open a document, what readers can do with it, and what is still hidden inside the file when you send it. The four tools in this category answer those questions, from password protection to permanent redaction. All four are free, with no account and no watermark.

Which PDF security tool should I use?

• Lock a file with a password: Password protect a PDF encrypts it with AES 256, the strongest encryption in the PDF standard. You can also block printing, copying, editing and comments, so people can read the document but not reuse it.
• Remove a password you know: Remove a PDF password saves a copy with no open password and no print or copy limits. It accepts the open password or the owner password, but it never guesses or cracks one.
• Sign a document: Sign a PDF online lets you draw, type or upload your signature and place it on any page together with your initials, the date and check marks.
• Black out private details: Redact a PDF permanently removes names, account numbers, email addresses and anything else you mark, instead of only hiding them behind a black box.

How it works

1. Open the tool you need and drop your PDF onto the upload area.
2. Set a password and permissions, type the current password, place your signature or mark the areas to redact.
3. Click the action button and download the new copy. Your original file stays as it was.

Redaction is not the same as covering text

A black rectangle drawn over a sentence leaves the words underneath, and anyone can still select, copy or search them. The redaction tool rebuilds every marked page so the covered text, images and graphics are gone from the file. The redacted copy is created as a brand new PDF, so metadata, bookmarks, attachments and scripts from the original are not carried over. If the rest of a redacted page must stay searchable, switch on the OCR option.

How your files are handled

Signing and redaction run entirely in your browser, so the document never leaves your device. Password protection and password removal run on our server, because encryption needs a full PDF engine. The file and the password travel over an encrypted HTTPS connection, are used only for that job and are deleted right after processing. We never store passwords, so we cannot recover a forgotten one. Only remove passwords from files you own or have permission to change.

Tips for safer PDFs

• Use a long passphrase and send it through a different channel than the file: for example, email the PDF and text the password.
• Redact first, then protect. A password keeps strangers out, but anyone who has it can read every word, so remove what readers should never see before you encrypt.
• Check every page after an automatic redaction search, especially scans, tables and images. For scanned files, run PDF OCR first so the search can find the text.
• Before you publish a file, strip author names and other hidden data with Clean PDF, and mark drafts with a "Confidential" text watermark.
• Need to complete a form before signing? Fill it in with the PDF form filler, then lock the answers with Flatten PDF Forms.

Frequently asked questions

How strong is the password protection?

Every protected file is encrypted with AES 256, the strongest encryption defined in the PDF standard, and your password can be up to 128 characters long. A separate owner password is created automatically to enforce the permissions you choose.

Can you open a PDF if I forgot the password?

No. The password removal tool only works with a password you can type. It does not guess or crack passwords, and because we never store them, we cannot recover one for you. Ask the person who created the file for the password or for an unprotected copy.

Is a signature added with Sign PDF legally valid?

The tool creates a simple electronic signature: a visual mark of your signature on the page. It is accepted for many everyday agreements, such as quotes, delivery notes, school forms and many contracts. Some official processes require an advanced or qualified digital signature backed by a certificate; in that case, use the signing service the other party asks for.

Does redaction remove the text for good?

Yes. Each marked page is rendered as an image with the marked areas filled in solid black or white, and that image replaces the original page, so there is no hidden text layer left to recover. Pages without marks are copied unchanged and stay searchable.