Protect PDF
Password-protect and encrypt a PDF document
Encrypt a PDF with AES-256 protection and set passwords for opening and editing. Configure permissions to control printing, copying, and modification. Encryption runs client-side with sanitized password input — see our [processing model](/processing-model) for details.
How to use Protect PDF
Upload your PDF
Click the upload area or drag and drop the PDF you want to protect.
Set a password
Enter a strong password. Optionally set an owner password and configure permissions such as print restriction or edit restriction.
Click Protect PDF
The PDF is encrypted in your browser with AES-256 encryption.
Download the protected PDF
Click Download to save the encrypted PDF. Keep your password safe — it cannot be recovered if lost.
Drop a PDF here
Then set a password to protect it
Max 50 MB
What is PDF password protection?
PDF password protection encrypts a PDF document so that a password is required to open or modify it. This is the standard way to secure confidential documents, restrict printing, or prevent editing of contracts and certificates.
The tool supports both user passwords (required to open the file) and owner passwords (required to change permissions). Encryption uses the AES-256 standard, the same algorithm used by banks and government agencies to protect sensitive data.
Password protection is critical in many professional contexts. Financial advisors encrypt client portfolio statements before emailing them. Healthcare organizations protect patient records to comply with HIPAA and similar regulations. Law firms secure privileged communications and settlement agreements. Real estate agents protect purchase contracts containing sensitive buyer information. Even for personal use, encrypting tax returns, insurance documents, or identity paperwork before storing them in cloud services adds an important layer of defense against unauthorized access. For a comprehensive overview of PDF encryption options, see our guide to protecting PDFs with passwords and encryption.
AES-256 encryption means the document content is scrambled using a 256-bit key derived from your password. Without the correct password, the encrypted file is computationally infeasible to decrypt. The strength of the protection depends directly on password quality: use at least 12 characters mixing uppercase, lowercase, numbers, and symbols. Avoid dictionary words or personal information. For documents that need to be visually marked rather than access-restricted, consider adding a watermark instead of or in addition to password protection.
Frequently asked questions
What encryption does the tool use?
The tool uses AES-256 bit encryption, which is the current industry standard for PDF security and is approved for protecting sensitive documents.
What is the difference between a user password and an owner password?
A user password is required to open the document. An owner password controls permissions — printing, copying, and editing. Anyone with the owner password can change these restrictions.
Can a protected PDF be unlocked?
If you know the password, yes — use the Unlock PDF tool on this site. Without the password, recovering the content requires specialized software and can be computationally intensive.
Can I restrict printing and copying without requiring a password to open?
Yes. Set only an owner password (leave the user password empty). The PDF will open without a prompt, but printing, copying text, and editing will be restricted unless the owner password is provided.
How do I password protect a PDF for free?
Upload your PDF to this tool, enter a password in the user password field, and click Protect PDF. The document is encrypted with AES-256 in your browser and the protected file is ready to download immediately. No account, no signup, and no watermarks are added to your document.
What happens if I lose my PDF password?
There is no password recovery mechanism. AES-256 encryption is designed so that only someone with the correct password can open the file. Store your passwords in a password manager or other secure location. If you forget the password, the document contents cannot be recovered through this tool.
Can I encrypt a PDF before sending it by email?
Yes, and this is strongly recommended for sensitive documents. Upload your PDF, set a user password, and download the encrypted file. Send the encrypted PDF by email and communicate the password separately through a different channel (phone call, text message, or secure messaging app). This way, even if the email is intercepted, the document remains protected.
Related tools
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Related guides
How to Password-Protect and Encrypt PDF Files
Step-by-step instructions for securing PDF documents with passwords and encryption, including permission controls and security best practices.
How to Convert Word Documents to PDF
A practical guide to converting Word (DOCX) files to PDF while preserving formatting, fonts, images, and page layout across all devices.
Making PDFs Accessible: Tags, Structure, and Compliance
Learn how to create accessible PDF documents that meet WCAG and Section 508 requirements, including proper tagging, reading order, and alternative text.