Security

Premium Feature: Password protection and redaction require a Premium subscription.

Protect sensitive documents with passwords, permanently remove confidential information with redaction, and understand PDF security features.

Password Protection

Encrypt your PDFs to restrict who can open or modify them.

Setting a Password

  1. Go to File → Set Password
  2. Choose your protection options:
    • Open password: Required to view the document
    • Permissions password: Required to edit or print
  3. Enter and confirm your password
  4. Save the document

Encryption Levels

  • 128-bit AES: Good security, widely compatible
  • 256-bit AES: Maximum security, requires newer readers

Permission Options

With a permissions password, you can restrict:

  • Printing
  • Copying text and images
  • Editing the document
  • Adding annotations
  • Form filling

Removing Password Protection

  1. Open the protected document (enter password)
  2. Go to File → Remove Password
  3. Enter the current password
  4. Save the document

Redaction

Permanently remove sensitive information from PDFs. Unlike covering text with a black box, redaction completely removes the underlying content.

Warning: Redaction is permanent and cannot be undone after saving. Always work on a copy of your original document.

How Redaction Works

  1. Mark content for redaction (creates red overlay)
  2. Review marked content
  3. Apply redaction (permanently removes content)
  4. Save the document

Mark for Redaction

  1. Go to Edit PDF → Redact or press D
  2. Select text or draw rectangles over content
  3. Marked areas show a red overlay
  4. Add more areas as needed

Find and Redact

Search and redact multiple instances of text:

  1. Go to Edit PDF → Find and Redact
  2. Enter the text to find (e.g., "SSN", phone numbers)
  3. Review found instances
  4. Select which to redact
  5. Apply redaction

Redaction Options

  • Fill color: Black is standard, or choose custom
  • Overlay text: Add text like "REDACTED" over the area

Applying Redactions

  1. Review all marked areas
  2. Click "Apply Redactions" in the toolbar
  3. Confirm the permanent removal
  4. Content is completely removed from the file

Flatten Document

Flattening merges all annotations and form data into the PDF content, making them permanent and uneditable.

  1. Go to File → Save as Flattened
  2. Choose save location
  3. The new file has all content merged

Use flattening when:

  • Sharing final versions of signed documents
  • Preventing annotation modification
  • Ensuring consistent appearance across readers

Metadata & Privacy

PDFs can contain hidden metadata. View and manage it:

  1. Go to File → Properties (⌘I)
  2. View document information: author, creation date, etc.
  3. Edit or remove sensitive metadata

Security Best Practices

  • Use strong passwords (12+ characters, mixed case, numbers, symbols)
  • Keep a secure record of passwords
  • Always work on copies when redacting
  • Verify redaction by searching for redacted terms
  • Remove metadata before sharing sensitive documents
  • Use permissions passwords to prevent unauthorized printing

What Redaction Removes

When you apply redaction, Reedio removes:

  • Text content
  • Images under the redaction area
  • Underlying vector graphics
  • Hidden text layers

After redaction, the removed content cannot be recovered from the file.