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This presentaton is part of PDF Days Europe 2025.
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Modern invisible ink – Understanding hidden information in PDF

Risks and implications of hidden information for AI processing and data security

Session description

This technical session explores how and why information becomes hidden in PDFs – whether by design, maliciously, or as a side effect. We examine PDF features and techniques that result in obscured or residual data, and discuss their consequences in the context of data security and AI processing.

Key questions addressed include:

• What types of hidden information exist in PDF?
• How can we make sure sensitive content is completely removed?
• How are AI processing pipelines vulnerable to malicious data injection attacks?