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Add password protection to a PDF or remove it — all in your browser.
The Lock/Unlock PDF tool is an enterprise-grade security utility that empowers you to encrypt or decrypt PDF documents securely within your browser. Aligned with KaruviLab's uncompromising Zero-Server-Upload and Privacy-First principles, this tool ensures that your highly sensitive documents—such as financial records, legal contracts, and personal health information—are never exposed to external servers during the encryption or decryption process.
Driven by robust Local-First Execution, our cryptographic engine operates exclusively on your device's hardware. This means the passwords you enter and the files you process remain completely isolated within your local sandbox. You can confidently apply strong password protection or remove existing restrictions from your PDFs without fearing data interception, telemetry tracking, or cloud storage leaks.
To guarantee uninterrupted productivity in high-security scenarios, this utility offers total Offline Resilience. Once the tool has initialized in your browser, you can safely sever your internet connection and continue locking or unlocking documents. This air-gapped capability makes it the perfect solution for handling classified or highly confidential files in sensitive work environments.
Input
Unencrypted financial_Q4.pdf and a new strong password.Output
A fully encrypted PDF that requires the password to be opened.Input
Encrypted bank_statement.pdf and the correct access password.Output
An unencrypted version of the PDF that can be opened freely.Input
Signed legal_contract.pdf.Output
An encrypted PDF securely locked against unauthorized access.No. We utilize a strict Zero-Server-Upload design. Your files and passwords are processed entirely on your device, ensuring maximum privacy.
Yes, the tool features complete Offline Resilience. You can use it without an internet connection once the page is fully loaded.
No. Our tool is designed for legitimate decryption and relies on standard cryptographic principles. You must know the correct password to unlock the file.
We utilize modern, strong encryption standards (such as AES) provided by our robust local PDF processing engine to ensure your documents are secure.
Because processing happens locally, the limit is based on your device's memory. It easily handles large, multi-page documents securely.