Add the PDF
Choose or drop a valid, unlocked PDF. The upload state is replaced by the private settings workspace.
Lock PDF Online with Password
Add an open password, optional owner password and PDF permissions, then download an AES-encrypted copy without sending the document through a page-specific upload endpoint.
Drop a PDF here to lock it
or choose a PDF from your device and add password security.
Processing capacity depends on this browser and device. The original file remains unchanged.
document.pdf
PDF preview
First-page preview for confirming the selected document.
Preparing the document preview…
The selected PDF, passwords and generated output remain in this browser session. They are not sent to CorrectionCopy analytics.
PDF password and permission settings
1
Set the open password
This password is required whenever someone opens the protected PDF.
Password strengthEnter a password
12+ charactersUpper & lowerNumberSymbol
Save the password securely before sharing the file. CorrectionCopy cannot recover a forgotten PDF password.
2
Choose security and permissions
AES-256 is recommended. Advanced permissions are optional and reader-enforced.
Advanced owner password and permissions
Encryption strength
Use a different owner password when applying restrictions.
3
Create the protected PDF
The source file stays unchanged; a new encrypted PDF is generated.
Enter only a readable base name. The PDF extension is added automatically.
Preparing encryption…
Protected PDF is ready
The encrypted result passed PDF validation.
Useful next steps after locking your PDF
Continue with another relevant security or document task after downloading.
How to password protect a PDF
Create a password-protected copy in three clear steps.
Set passwords and permissions
Enter and confirm the open password. Optionally choose an owner password, AES level and reader permissions.
Lock and download
Create the encrypted result, then choose Download Locked PDF. Store the password somewhere safe.
Lock a PDF with AES password security
This browser-based Lock PDF tool adds standard PDF password encryption to an existing document. Use it to password protect a PDF, require a password before opening, set a separate owner password, or limit actions such as printing, copying, annotation, form filling and page assembly.
The default setting creates an AES-256 encrypted PDF. A 128-bit AES compatibility option is available for older workflows. The original document is not overwritten. The tool generates a separate locked PDF that can be opened in compatible readers with the correct password.
Common searches such as add password to PDF, encrypt PDF online, secure PDF before email, restrict PDF printing and protect confidential PDF describe different parts of the same workflow. This page keeps those controls together without hiding the important password-recovery and permission limitations.
PDF protection capabilities
Security controls that correspond to real PDF encryption and permission settings.
AES-256 encryption
Use the recommended 256-bit AES PDF security mode or choose 128-bit AES for compatibility.
Open and owner passwords
Require an open password and optionally reserve a different owner password for permission management.
Printing controls
Allow full printing, low-resolution printing or set the PDF permission flag to block printing.
Copy and editing permissions
Control extraction, modification, annotation, forms and page assembly using standard PDF flags.
Browser-session processing
The PDF and passwords remain in the page session while the local WebAssembly engine generates the result.
Validated PDF output
The result is checked for a PDF signature and encryption dictionary before the success state appears.
When to use an encrypted PDF
Password protection is useful when a document must remain a normal PDF but should not open without a shared secret.
Email attachments
Protect financial statements, reports or identification documents before sending them through email or messaging.
Client and business files
Add an open password before sharing proposals, invoices, contracts, internal policies or confidential drafts.
Controlled printing and copying
Set reader-enforced permission flags when recipients should view a PDF but have limited printing or extraction options.
Security limitations and troubleshooting
PDF password encryption protects the document content from opening without the password, but its effectiveness still depends on a strong, unique password and secure password sharing. Permission flags are different from the open password: compliant PDF readers may enforce them, but they are not a substitute for access control or digital-rights management.
Already protected PDFs
Use an authorized unlocked copy. This workflow does not ask for an existing input password before applying new encryption.
Forgotten password
CorrectionCopy cannot recover it. Store the password safely before downloading or sharing the locked PDF.
Blocked security engine
Strict content blockers, network policies or Content Security Policy can block the pinned browser security JavaScript or WebAssembly files. Allow the fixed component hosts and retry.
Large or complex files
Processing capacity depends on available browser memory. Close memory-intensive tabs or use a desktop device when a large document fails.
Permission enforcement
Printing, copying and editing restrictions are honored by compliant readers. Some software can ignore or remove permission flags.
Accessibility flag
Current PDF specifications generally expect readers to allow accessibility extraction even when a restrictive flag is present.
Lock PDF frequently asked questions
Answers about passwords, AES encryption, permissions, privacy, compatibility and common failures.
How do I add a password to a PDF?
Add the PDF, enter and confirm an open password, optionally configure an owner password and permissions, then choose Lock PDF. Download the generated file after validation.
What is the open password?
The open or user password is required to decrypt and view the PDF. Anyone without that password should be unable to open a properly encrypted result in a compatible reader.
What is the owner password?
The owner password controls permission settings. When it is blank, this tool reuses the open password. Use a separate owner password when you need to retain permission control.
Should I choose AES-256 or AES-128?
AES-256 is the recommended default for current readers. AES-128 is available for compatibility with older document workflows that specifically require it.
Can I block printing or copying?
You can set standard PDF permission flags for printing, copying, modification, annotation, form filling and page assembly. These restrictions depend on the PDF reader honoring them.
Does this tool upload my PDF or password?
This page has no page-specific upload endpoint for the selected PDF. The file, passwords and result remain in browser memory while the local encryption engine runs. Required engine files are fetched separately and do not include your document content.
Can I lock an already password-protected PDF?
Not with this workflow. Use an authorized unlocked copy first, then apply a new password and permission configuration.
Will the encrypted PDF open in Adobe Acrobat and browsers?
The output uses the standard PDF security handler. Current conforming readers should request the open password, though feature and permission behavior can differ by reader.
What happens if I forget the password?
There is no recovery service on this page. Strong encryption is designed to prevent access without the password, so store it in a trusted password manager before sharing the file.
Why does the encryption engine load the first time?
The page loads a pinned browser security component when protection is requested. The browser may cache those component files for later use. Your PDF is written only to the component's in-memory virtual file system.
Does password protection change PDF quality?
Encryption changes the security wrapper rather than intentionally rasterizing or recompressing every page. Existing page content should remain intact, although damaged or unusual PDFs may fail to process.
Does it work on phones and tablets?
The interface supports current mobile browsers, but encryption uses memory and WebAssembly. Large PDFs are more reliable on devices with more available memory.
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