Password Protect PDF Files Online Free

Protect your PDF by adding a security password for opening the PDF file, So that no one can open the PDF without password.

Max File Size: 100.0 MB

User Password (To Open)

Use same password for Owner/Permissions

Encryption

Allow User To:

Print Copy Text Modify Annotate

Select files or drop here

How to Protect PDF with Password

Follow these simple steps to password protect your PDF.

Click the Choose Files button or drag and drop your PDF file onto the upload area.
Enter the password that you want for your PDF.
Click the Lock PDF button.
Within a few seconds, your password protected PDF file will be ready. Click the Download button to save the encrypted PDF.

Now your PDF is secure and no one can open it without knowing the password that you know.

AES (Advanced Encryption Standard) is a widely used encryption algorithm for protecting digital data.

It comes in three main key sizes. Larger keys generally provide stronger security but may require slightly more processing time.

AES-256 is the strongest commonly used variant today and is widely used for securing PDFs, disks, and highly sensitive information.

Variant	Key Size	Rounds	Security Level	Best For
AES-128	128 bits	10	Very strong	Everyday encryption and fast performance
AES-192	192 bits	12	Extremely strong	Higher security environments
AES-256	256 bits	14	Strongest practical encryption	Sensitive data, PDFs, and full-disk encryption