Lock PDF
Add an open password to a PDF in your browser. Choose a password, confirm it, preview the first page, then download a protected copy. Already encrypted files are not re-locked here. Nothing is uploaded.
or drop files here
Runs in your browser. Nothing is uploaded.
How it works
Drop an unlocked PDF
Choose a PDF up to 10 MB that is not already password-protected. The file stays in this tab.
Set and confirm a password
Enter an open password of at least 4 characters and confirm it. Viewers will need this password to open the downloaded file.
Lock and download
Tap Lock PDF to create a protected copy. Keep the password somewhere safe; Easy24 cannot recover it.
What is Lock PDF?
Lock PDF password-protects PDF files in your browser before you share them. Lock PDF is part of Easy24’s PDF toolbox. Files are processed locally in your browser for normal use; Easy24 does not upload them to finish the job. On the free plan you get 5 uses per day and files up to about 10 MB. Limits are shown before you download. Typical flow: Drop an unlocked PDF, enter and confirm a password (at least 4 characters), check the preview, then Lock PDF. Download the protected copy. Conversion stays on your device. Related tools and reverse conversions appear on the page when a follow-up step is common.
Why use this tool
- AES-256 open-password protection in the browser
- Password confirmation and show/hide toggle
- First-page preview for unlocked source files
- Clear rejection of already encrypted PDFs
- Private local processing. Free: 5/day, 10 MB
- Pairs with Unlock PDF for restriction removal when supported
Questions
What does Lock PDF do?
It adds an open password to an unlocked PDF so apps ask for that password before showing the pages. Processing stays in your browser.
Can I lock a PDF that already has a password?
Not in this tool. Unlock it first with Unlock PDF when possible, then lock again with a new password.
Is this the same as redacting secrets?
No. Anyone with the password can read the full document. To hide content permanently, remove or redact it instead of only encrypting.
Which password strength is used?
The tool writes modern AES-256 open-password protection. Use a unique password you will remember.
Why do I need HTTPS?
Browser crypto for AES-256 requires a secure context. Localhost and HTTPS sites work; plain HTTP usually does not.
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When to use Lock PDF
If you only need Lock PDF once in a while, a browser page is often enough: set options, get a result, move on. Add an open password to a PDF in your browser. Contracts, forms, and school handouts are common inputs. Keep originals until you confirm the download looks right on your machine. Search results often mix upload-based converters with local tools. Read the privacy note on this page so you know which model you are using. On Easy24, normal use of this tool keeps processing in your browser. That means the content you paste or the file you pick does not need to be uploaded to finish the job. The free plan allows 5 uses per day and files up to about 10 MB; limits appear before download. For product-wide questions about accounts, ads, and Pro, see the site FAQ and Security pages. For this tool’s exact steps, use the guide blocks above.
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