Prevention of Unauthorized Document Changes

Objective

Protect signed documents from any action that could damage their integrity or trustworthiness.

Guidelines

Signed documents must be protected against:

• Adding new content.
• Removing existing content.
• Modifying existing content.
• Adding annotations or other objects.
• Adding unauthorized signatures.
• Replacing or manipulating parts of the document.
• Any other change intended to weaken the document or make it untrustworthy.

Document restriction settings

In addition to the digital signature itself, apply the appropriate document security settings (for example, PDF permissions), such as

• Disable printing.
• Disable saving changes to the document.
• Disable editing of content.
• Disable inserting, deleting, or rotating pages.

Important: These restriction settings are helpful extras, but they can be bypassed by some tools. The digital signature is the primary and reliable way to detect unauthorized changes—never rely on viewer restrictions alone.