Zscaler Indexed Document Matching (IDM) is a DLP technique used to protect entire documents or large portions of text-based content, rather than discrete data fields. Administrators upload representative samples of “crown jewel” documents (for example, contract templates, medical forms, HR records, or tax documents). Zscaler processes and indexes the textual content, then uses this index to detect when similar or identical document content is uploaded, shared, or exfiltrated through monitored channels.

This approach is ideal for high-value, unstructured documents that contain sensitive information in a repeatable format. It is distinct from Exact Data Match (EDM), which is used for structured field-level data such as credit card numbers or national IDs, and it is not optimized for pure image content or OCR-based detection. While IDM can apply to many file types (Word, PDF, spreadsheets that contain meaningful text, etc.), the core use case is protecting documents where overall content similarity matters.

Therefore, the best description is that IDM protects high-value documents that tend to carry sensitive data, such as medical forms and tax documents.

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