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Password Protect PDF

Lock a PDF so it asks for a password, and optionally stop people printing or copying it.

About Protect PDF

Protect PDF files before they leave your hands: a tax return for your accountant, salary data for HR, a draft contract for a client. Set a password, type it twice so a typo can't lock you out, and the file is encrypted with AES-256, the strongest method the PDF standard offers. Standard PDF readers ask for the password before showing a single page.

Tick Stop printing and copying to go further. People who know the password can still read the document, but readers won't let them print it, copy text or edit it. Under More options you can set a separate owner password, which you'll need later to change those permissions. There's no way to recover a lost password, so keep yours somewhere safe.

How to use Protect PDF

  1. 1
    Upload your PDF

    Choose the file you want to lock or drop it on the page.

  2. 2
    Set the password twice

    Type it in Set a password and again in Repeat password.

  3. 3
    Choose restrictions

    Tick Stop printing and copying if readers should only view it. An owner password is optional, under More options.

  4. 4
    Protect and download

    Click Protect PDF and save the encrypted copy, which ends in _protected.

Why use Cubfile for this

  • AES-256 encryption

    The top encryption level in the PDF format, rather than the older RC4 schemes some tools still use.

  • View-only option

    Block printing, copying and editing for anyone who only has the open password.

  • Separate owner password

    Keep the right to change permissions for yourself with a second password.

  • Password never kept

    It's used to encrypt the file and removed from our records the moment the task finishes.

FAQ

Protect PDF: questions and answers

How strong is the encryption when I protect PDF files here?
Files are encrypted with AES-256. How safe that is depends mostly on your password, so use a long one you don't use anywhere else.
Can I protect PDF files so they can't be printed?
Yes. Tick Stop printing and copying. Standard readers then refuse to print, copy or edit, but treat it as a deterrent; the open password is what actually keeps strangers out.
What if I forget the password?
The file can't be opened, and we can't help, because we never keep the password. Save it in a password manager before you send the PDF. With the password at hand, Unlock PDF can take it off again whenever you need to.
How many PDFs can I lock on the free plan?
Guests have 2 tasks in total and free accounts 2 per day, one PDF of up to 50 MB each time. VIP protects up to 50 files per task with no daily cap. To lock several documents in one task, combine them first with Merge PDF.
Do you keep a copy of the PDF or the password?
No. The password is wiped when the task ends and the file is deleted automatically an hour later. Each task runs in its own isolated process, and nobody here opens your documents.
Share Protect PDF with a friendIt runs in any browser, and they can try it without signing up.

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