Password Protect PDF

Secure your PDF document offline in your browser with RC4 128-bit password encryption.

Drag & drop a PDF to protect

or browse your files

Single PDF file — limited only by your device memory

Secure Local PDF Password Protection

Private Local Encryption

Encrypt files directly on your CPU. No files or passwords are ever transmitted to any external server, eliminating data leak vulnerabilities.

Password-Gated Opening

Applies the PDF standard security handler, so the password is required to open the file. Note that PDF permission flags for printing, copying and editing are advisory only, and this tool does not set them.

Instant Results

Protect your documents immediately. The locked PDF is generated inside your browser and downloaded instantly without upload delays.

Frequently Asked Questions

How secure is PDFCraft's password protection?
We use standard PDF encryption to lock your documents. Since the encryption process runs entirely in your browser sandbox, your password and document are completely safe from interceptors.
Will my PDF password be saved by PDFCraft?
No. PDFCraft operates entirely client-side. We do not store, track, or log your passwords or files. Once you close the tab, all session details are permanently gone.
Will the password-protected PDF work in standard viewers?
Yes. The output is a standard encrypted PDF. It will prompt for the password when opened in Adobe Acrobat, Google Chrome, Apple Preview, or any other PDF reader.
Can I password protect PDFs offline?
Yes. After installing PDFCraft as a PWA, you can encrypt your sensitive documents offline, keeping them safe on your local drive.

Step-by-Step Guide Available

Choosing a password that holds up, and what PDF encryption cannot do.

Read Guide

What password protection actually does to the file

Applying a password encrypts the document. An encryption key is derived from the password you type and used to encrypt the content streams and strings inside the file, following the PDF specification's standard security handler. Without the password, a reader has structure it cannot decode rather than content it politely refuses to show.

Two things are worth understanding before you rely on it. First, the encryption is only as strong as the password. An attacker who has your file can attempt passwords offline, as fast as their hardware allows, with nobody to rate-limit them. A short or common password offers very little protection regardless of the cipher. Second, PDF also supports permission flags — no printing, no copying — enforced by the reader rather than by cryptography. Plenty of software ignores them entirely, so treat them as a request, not a control.

Choosing a password you can actually depend on

  • Length beats complexity. A passphrase of four or five unrelated words resists offline guessing far better than a short string of substituted symbols.
  • There is no recovery. Nothing here stores your password, and there is no reset. Lose it and the document is genuinely unreadable.
  • Already-encrypted files are refused. Rather than risk producing a damaged double-encrypted file, the tool stops and asks you to remove the existing password first.
  • Send the password separately. A protected file and its password in the same email have the security of an unprotected file.

Encryption, permissions and their limits

Can the password be removed by someone who does not know it?
Not easily, if the password is long. The realistic attack is guessing, performed offline against a copy of your file. That is why the length of your password matters more than any other single choice here.
What is the difference between a user password and an owner password?
The user password is required to open the document and is what actually drives the encryption. The owner password governs permission flags such as printing and copying, and those flags depend on the reader choosing to honour them.
Does protecting a PDF stop someone taking a screenshot?
No. Once a document is open on screen it can be photographed, screenshotted or retyped. Encryption controls who can open the file, not what they do afterwards.