Protect PDF
Add a password and AES-256 encryption to keep your PDF private.
mydearPDF locks your PDF with a password using AES-256 encryption — the same standard banks and governments rely on. Once protected, the file cannot be opened, read, or copied without the password you set. Encryption runs entirely on our secure server using qpdf, the industry-standard PDF library, and the protected file is delivered to you immediately.
Secure
HTTPS transport. Files removed after processing.
High quality
Resilient open-source engine pipeline.
Fast & easy
Drop, process, download — in seconds.
How to protect pdf with mydearPDF
- 1
Upload your PDF
Drop the PDF you want to protect onto the upload area.
- 2
Set a password
Enter a password and confirm it. This is what people will need to open the PDF.
- 3
Click Protect PDF
mydearPDF encrypts the file with AES-256.
- 4
Download the protected PDF
Click Download to save mydearpdf-protect.pdf, now password-protected.
Built for speed, privacy, and zero friction
- Real AES-256 encryption (not a fake lock)
- Industry-standard qpdf engine under the hood
- No watermark, no signup, no daily limit
- Files removed from our server immediately after processing
Frequently asked questions
What encryption does mydearPDF use?
We use AES-256 via qpdf — strong, modern encryption that requires the correct password to open the file. This is genuine encryption, not a cosmetic restriction that any reader can bypass.
Can you recover my password if I forget it?
No. We never store your password — it exists only in memory for the duration of your request. If you lose it, the PDF cannot be opened. Keep your password somewhere safe.
What happens to my password and file?
Your password is used only to encrypt the file and is never logged or stored. Your file is processed in isolated server memory over HTTPS and deleted immediately after the protected PDF is delivered.
How do I remove the password later?
Use our Unlock PDF tool. As long as you have the password, you can remove the protection at any time and get back an unlocked copy.
Will the protected PDF open everywhere?
Yes. The encrypted PDF opens in any standard reader — Adobe Acrobat, Preview, Chrome, Edge — as soon as the correct password is entered.
Password-protecting a PDF is the simplest way to keep a sensitive document private when you email it, upload it, or store it in the cloud. mydearPDF applies AES-256 encryption with a user password, so the file is unreadable to anyone who does not have it. Under the hood we use qpdf, the same battle-tested engine used in PDF pipelines worldwide — there is no fake "protection" that a free reader can strip away. We never see or store your password, and your file is wiped from our server the moment processing finishes. When you need to remove the password again, our Unlock PDF tool does exactly that.