Static Data Masking (SDM)

 

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What is Static Data Masking?


Persistent data masking, or Static Data Masking (SDM), is the primary method of masking sensitive classes of data at rest in production or test environments. These data classes are typically database columns or atomic (fixed or floating) values in text files, documents or images.

Static data masking tools are designed to protect personally identifiable information (PII), protected health information (PHI), primary account numbers (PAN), trade secrets, and controlled unclassified information (CUI).

Static data masking can help you nullify data breaches, provide safe test data, and comply with data privacy laws. Compare Static Data Masking (SDM) to Dynamic Data Masking (DDM), which selectively redacts sensitive values for database query applications, or real-time data masking (RTDM) which immediately or incrementally masks data in databases or files when they change.

PII data masking tools from IRI -- FieldShield, DarkShield and CellShied EE -- as well as the IRI Voracity platform that includes them -- centrally classify sensitive data and provide more data discovery and SDM functions for more data sources than any other data masking tool vendor. 

The off-the-shelf categories of sensitive data anonymization techniques in IRI data masking tools include:

IRI solutions for data masking problems

You can also "roll your own" external data masking function. This allows you to call a custom field protection at runtime instead of a built-in function.

IRI FieldShield and DarkShield also support several synthetic (test) data generation functions which also serve as data privacy compliance solutions in test data envirnoments. See this article for details.

Whether built-in or custom, you can apply static data masking functions conditionally to specific rows or columns, and across multiple sources through data masking rules that you can define, re-use and share. It is also possible to apply these functions in a dynamic data masking (DDM) context using a FieldShield or DarkShield API call.

Referential integrity (RI) -- critical in PII masking for databases -- is automatically preserved through the consistent application of deterministic data masking functions to classified data. Deterministic data masking functions are static data masking functions like encryption that uniquely associate masked values with original plaintext values, and may be reversible (unlike a random value). See this FAQ for more information on RI.

Did You Know?

IRI Voracity platform users can run static data masking functions in conjunction with data discovery, integration, migration, governance, and analytic operations. For example, they can simultaneously cleanse, encrypt, and sort data for bulk loads into test schema, data lakes, and AI models.

Frequently Asked Questions (FAQs)

1. What is static data masking?
Static data masking (SDM) is the process of irreversibly de-identifying sensitive data at rest—typically in databases, files, or documents—so it can be safely used in non-production environments without exposing original values.
2. How does static data masking differ from dynamic or real-time masking?
Static data masking permanently alters sensitive data at rest, while dynamic masking redacts values on the fly during database queries. Real-time masking modifies data during or immediately after a transaction or update. SDM is ideal for development, testing, and data sharing.
3. What types of data can be protected with static data masking?
SDM protects sensitive information such as PII, PHI, PAN, CUI, and trade secrets across structured, semi-structured, and unstructured formats—including databases, flat files, documents, and images.
4. How does static data masking help with data privacy compliance?
Static data masking supports compliance with laws like HIPAA, GDPR, PCI DSS, and CCPA by de-identifying sensitive data and making it unusable to unauthorized users. It helps reduce breach risk and supports privacy-by-design principles.
5. Can static data masking preserve referential integrity?
Yes. IRI tools apply deterministic masking functions like format-preserving encryption to ensure referential integrity (RI) is maintained across columns, tables, and even data sources—so relationships between data remain valid.
6. What masking techniques are supported in IRI’s static data masking tools?
IRI supports a wide range of masking functions including encryption, hashing, pseudonymization, tokenization, scrambling, redaction, randomization, generalization, and user-defined logic. These can be applied based on business rules or data classifications.
7. Can I use custom masking logic in static data masking?
Yes. IRI tools allow users to integrate external masking functions by calling custom field protection routines at runtime, enabling maximum flexibility for unique data protection requirements.
8. How is format-preserving encryption used in static data masking?
Format-preserving encryption (FPE) keeps the original structure of the data—like credit card number length or phone number format—while encrypting the values, making the masked data compatible with existing systems and schemas.
9. What are the advantages of using static data masking for test data?
SDM allows organizations to safely use production-like datasets in development and QA environments without exposing sensitive values. This ensures realistic testing while staying compliant and secure.
10. Can static data masking be applied selectively?
Yes. IRI tools allow conditional masking by row, column, or rule-based logic. This means you can apply different masking functions to different data classes or risk levels, as needed.
11. How are masking rules managed across different projects?
IRI tools support reusable and shareable masking rule libraries, allowing teams to enforce consistent masking logic across projects, data sources, and environments.
12. What is deterministic masking and why does it matter?
Deterministic masking uses a fixed logic (like keyed encryption) to ensure the same input always produces the same masked output. It’s important for maintaining referential integrity across datasets while still de-identifying the values.
13. Can IRI’s static data masking be used alongside data integration or migration tasks?
Yes. With IRI Voracity, you can run SDM alongside data discovery, cleansing, sorting, and transformation jobs, streamlining workflows like test data creation, ETL, or AI/ML model preparation.
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