Lock PDF
Secure your PDF documents effortlessly with our free, simple, and ad-free web application. Encrypt your files using robust AES 128-bit encryption and add password protection in just a few clicks. No file size restrictions, no watermarks.
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How To Password-Protect a PDF Document:
- Import or drag & drop your file to our Protect PDF tool.
- Type and confirm the strong password you’d like to use.
- Click “Protect” to add the password to your PDF.
- Edit the PDF with our other tools if desired.
- Download your password-protected PDF when ready—done!
How to password protect a PDF file
Follow these steps on how to password-protect your PDF files online for free:
Click on the "Select a file" button above or drag and drop a PDF file into the drop zone.
Enter a strong password and retype it to confirm.
Click on "Set password".
Once done, you can download the password-protected PDF document or sign in to share it with others.
Questions about password-protected PDFs? We have answers.
How do I choose a strong password?
Choosing a strong password keeps your content secure and prevents unauthorised access. To create a strong password, increase the length of the password and add a mix of letters (both upper and lower case) and numbers. The addition of symbols can also increase password strength. When you enter passwords, avoid using personal information or common words that can be guessed easily. It is best to use combination passwords (a mix of alphabets, numerals, and a special character) as they are difficult to crack.
How do I unlock a password-protected PDF?
When you open a PDF protected by a password, a dialogue box will appear that will prompt you to enter the password before you are able to see the file content. Type in the document open password and click OK to open the file. As a document owner, you can also remove the password with an PDfSeoTools trial or subscription.
What is the difference between password protection and encryption?
When you protect documents with a password, people who enter the correct password can access the file or folder. A stronger security method is encryption, with common types being 128-bit key or 256-bit AES encryption. Encryption turns document content into unreadable cipher text. To decrypt the document, authorised users need a key, which is typically a password or a digital certificate.
When you use the Acrobat online tool to add password protection to a PDF file, it encrypts the file for added security. If you need more advanced PDF security, you can try PdfSeoTools for free for seven days for Mac or Windows. The seven-day free trial lets you add encryption options, encrypt PDFs with certificates or manage security settings and permissions to restrict editing, printing or copying. Acrobat Pro also lets you edit PDFs, organise PDF pages and convert PDFs to and from Microsoft Office apps, including Microsoft Word documents, PowerPoint presentations and Excel spreadsheets.
Can I remove or change the password on a protected PDF?
Yes, you may remove or change the PDF password lock anytime you want as long as you own it.
What should I do if I forget the password for a protected PDF?
In case you forget the password, you can click on the forgot password section to recreate a password of your own. However, you must be the one to have your profile registered with your name, phone number, and other details.