Lock PDF

Add password protection and encryption to a PDF. Supports AES-256, AES-128, RC4-128 encryption and granular permissions.

What It Does

Encrypts a PDF with password protection. Supports AES-256 (default), AES-128, and RC4-128 encryption. Allows setting separate user and owner passwords with granular permission controls.

When to Use

• Protect a PDF with a password before sharing
• Set permissions (allow print but deny copy/modify)
• Re-encrypt an already encrypted PDF with a new password

Required Inputs

• password — user password (required to open the PDF)
• Plus one of: url, base64_pdf, or multipart file upload

Authentication

Send your API key in the CLIENT-API-KEY header.

Get your free API key at https://pdfapihub.com. Full API documentation is available at https://pdfapihub.com/docs.

Use Cases

• Confidential Document Protection — Encrypt contracts, NDAs, or financial reports before sharing
• Read-Only Distribution — Allow viewing and printing but prevent copying or editing
• Client Deliverables — Password-protect reports or proposals sent to clients
• Compliance — Encrypt sensitive PDFs (HIPAA, GDPR) before storage or transmission
• Exam Papers — Lock exam PDFs with a password released only at exam time
• IP Protection — Restrict copying from proprietary documents while allowing viewing

Permissions

Permission	Description
print	Allow printing
print_highres	Allow high-res printing
copy	Allow copying text
modify	Allow modifying content
annotate	Allow adding annotations
fill_forms	Allow filling form fields
extract	Allow extracting content
assemble	Allow assembling pages

Example Usage

curl -X POST https://pdfapihub.com/api/v1/lockPdf \
  -H "CLIENT-API-KEY: your_api_key" \
  -H "Content-Type: application/json" \
  -d '{
    "url": "https://pdfapihub.com/sample.pdf",
    "password": "viewerPass",
    "owner_password": "adminPass",
    "permissions": { "print": true, "copy": false, "modify": false },
    "output": "url"
  }'