Add a password and permission restrictions to a PDF with real AES-256 encryption. Everything runs locally in your browser for complete privacy.
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About Protect PDF
Protect PDF adds real password protection to any PDF document without uploading it anywhere. It encrypts the file with AES-256, the same standard used by banks and governments, and lets you set a separate password to open the file from the one that controls printing, copying, or editing permissions.
Unlike server-based tools that copy your file to a remote machine before locking it, Neuctra Tools performs the entire encryption process inside your browser using the Web Crypto API. Your document and the password you set never leave your device.
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How to Password Protect a PDF
Drop your PDF into the upload area or browse for it.
Turn on Require a password to open if you want a password needed just to view the file, and type it in.
Optionally set a separate owner password, and adjust the printing, copying, filling forms, and modifying permissions.
Click Protect PDF and download the encrypted file.
Built for Security and Privacy
Granular Permissions
Restrict printing, copying, form filling, and modifying independently of who can open the file.
Real AES-256 Encryption
This is genuine cryptographic protection, not a cosmetic lock, applied entirely on your device.
Private by Design
Ideal for contracts, financial records, or personal documents, since nothing is ever uploaded.
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Upload your PDF, turn on Require a password to open, type the password you want, then click Protect PDF. The encrypted file downloads straight to your device at no cost and with no account needed, since the encryption runs entirely in your browser.
The user password (the password to open) is required just to view the PDF at all, while the owner password controls permissions such as printing, copying, or editing once the file is open. Setting both lets you separate who can read the file from who can change it.
Yes, the Allow printing, Allow copying text, Allow filling forms, and Allow modifying switches set the permission flags stored in the encrypted PDF. Most modern PDF readers respect these restrictions, though they rely on the reader honoring the standard rather than being unbreakable technical locks.
Yes, AES-256 is the same encryption standard used by governments and banks, and this tool applies it through your browser's native Web Crypto API. The strength of the protection ultimately depends on choosing a password that is long and hard to guess.
No, Protect PDF never uploads your file to any server. Reading, encrypting, and saving the PDF all happen locally in your browser tab, so your document and its new password never leave your device.
The PDF becomes unreadable without it, since this tool applies real AES-256 encryption rather than a cosmetic lock. Write down or store the password somewhere safe, because there is no recovery or backdoor once the file is protected.
No, this tool expects an unencrypted PDF as input and cannot re-encrypt a file that is already password protected. Use the Unlock PDF tool first to remove the existing password, then protect the file again with new settings.
Yes, the output is a standard PDF encrypted with the same security handler that Adobe Acrobat and most PDF viewers already support. Anyone with the correct password can open it in any compliant reader, on any platform.
Yes, if you leave the owner password blank it automatically reuses your password to open, so you only have to remember one password. You only need a separate owner password if you want different credentials for opening versus changing permissions.
