Protect PDF with Password Online — Free PDF Encryption Tool

Sending a contract, financial report, or confidential document? Add a password to your PDF before sharing to ensure only authorized recipients can open it. Our free PDF password protection tool encrypts your file with AES-256 or RC4-128 encryption, lets you control printing and copying permissions, and downloads the protected PDF in seconds — all in your browser, with no server uploads.

Your password and your file never leave your device. The encryption is applied locally using jsPDF's built-in encryption engine, keeping your sensitive documents completely private throughout the process.

How to Add a Password to a PDF — Step by Step

1. Upload your PDF — Drag and drop your file into the upload area or click to browse. Files up to 100 MB are supported.
2. Set a password — Enter a strong password in the Open Password field and confirm it. The strength meter updates as you type to guide you toward a secure choice.
3. Choose encryption level — Select AES-256 for maximum security (recommended) or RC4-128 for compatibility with older PDF readers.
4. Set permissions — Choose whether authorized viewers can print, copy text, or edit the document after entering the password.
5. Adjust quality (optional) — Set the image rendering quality to balance sharpness and file size.
6. Click "Protect & Download PDF" — The encrypted PDF downloads automatically. Keep the password safe — it cannot be recovered.

Two Encryption Standards

🔒 AES-256 (Recommended)

Advanced Encryption Standard with a 256-bit key — the same algorithm used by governments, banks, and security professionals worldwide. Compatible with Adobe Acrobat 9 and later, and all modern PDF readers including Preview (macOS), Chrome, Firefox, Edge, and mobile PDF apps. This is the default and strongly recommended choice for any document that needs real protection.

🔑 RC4-128

An older 128-bit encryption standard compatible with Adobe Acrobat 5 and later. Use this only if you specifically need to share the file with someone using a very old PDF reader that does not support AES-256. For all modern use cases, AES-256 is the better choice.

Permission Controls

Beyond the open password, you can restrict what authorized users can do after opening the PDF:

• 🖨️ Allow printing: Uncheck to prevent the recipient from printing the document even after entering the password.
• 📋 Allow copying: Uncheck to prevent text and images from being selected and copied out of the PDF.
• ✏️ Allow editing & annotations: Uncheck to prevent the recipient from modifying the document, adding comments, or filling forms.

Password Strength Guide

What makes a strong PDF password?

The strength meter evaluates your password based on length and character variety. For meaningful protection, aim for at least 8 characters combining uppercase letters, lowercase letters, numbers, and symbols. A password like Df7!rQx2 is significantly harder to crack than password123, even at the same length.

Key Features

• Password strength meter: Real-time visual feedback with five levels — Too Short, Weak, Fair, Good, Strong.
• Password confirmation field: Prevents typos by requiring you to enter the password twice before proceeding.
• Show / hide toggle: Eye icon on both password fields for easier entry without errors.
• Two encryption standards: AES-256 for modern security, RC4-128 for legacy compatibility.
• Granular permissions: Control printing, copying, and editing independently.
• Quality slider: Set page rendering quality from 50% to 100%.
• Already-protected detection: If the uploaded PDF already has a password, the tool detects it and directs you to unlock it first.
• Password shown in confirmation panel: The password is displayed in the download confirmation so you can copy it immediately.
• 100% browser-based: PDF.js renders pages, jsPDF encrypts and exports — everything runs locally on your device.
• No watermarks: The output contains only your original content, encrypted.

Common Use Cases

📋 Protecting Legal & Contractual Documents

Contracts, NDAs, and agreements often contain sensitive terms. Adding a password ensures only the intended recipient can open the document, reducing the risk of accidental exposure during email transit.

💼 Securing Financial Reports

Bank statements, invoices, payroll documents, and financial summaries should never be sent unprotected. Encrypt them before attaching to emails or uploading to shared drives.

🎓 Protecting Academic and Research Work

Theses, research papers, and proprietary study materials can be shared with specific reviewers while remaining protected from broader distribution using a password that only those reviewers know.

🏥 Safeguarding Personal Records

Medical records, tax documents, passports, and insurance documents saved as PDFs should be encrypted before storage in cloud services or before emailing to service providers.

🏢 Distributing Internal Company Documents

HR policies, pricing sheets, strategic plans, and internal reports can be shared with staff while restricting the ability to print, copy, or forward the content to unauthorized parties.

Frequently Asked Questions

Conclusion

Protecting a PDF with a password should be fast, private, and free. With AES-256 encryption, a real-time password strength meter, confirmation matching, granular permissions, and zero server uploads, this tool covers every common PDF protection scenario directly in the browser.

No watermarks. No registration. No cost. Scroll up, upload your PDF, set a strong password, and download a fully encrypted document in moments.