Snowflake Data Masking: Protect Sensitive Data with Dynamic Masking Policies

The query came in at 2 a.m. A table full of customer records. Names, emails, phone numbers. You see the risk before the result even finishes loading. One mistake here and the data is exposed.

Snowflake Data Masking gives you a way to stop that mistake before it happens. With Dynamic Data Masking and Masking Policies, you can control who sees sensitive data down to the column level. This is not security theater. The data never leaves Snowflake unprotected.

To mask sensitive data in Snowflake, define a Masking Policy using CREATE MASKING POLICY. Bind it to a column with ALTER TABLE ... MODIFY COLUMN ... SET MASKING POLICY. In the policy definition, specify the logic that decides when to mask. For example, only show cleartext to users with a role like FULL_ACCESS_ROLE. Others see masked output, such as XXXXXX.

Example:

CREATE MASKING POLICY email_mask AS (val STRING) RETURNS STRING ->
 CASE
 WHEN CURRENT_ROLE() IN ('FULL_ACCESS_ROLE') THEN val
 ELSE '***MASKED***'
 END;

ALTER TABLE customers MODIFY COLUMN email
SET MASKING POLICY email_mask;

Dynamic Data Masking happens at query time. The underlying data stays intact. This ensures analytics and machine learning can still run on the true data with the right permissions, while unauthorized queries return masked values.

Snowflake supports conditional masking, so you can tailor access by role, environment, or any factor you choose. Masking policies are reusable, versionable, and easy to audit. They integrate with Snowflake’s role-based access control and operate without changing stored data.

Masking sensitive data is critical for compliance with GDPR, CCPA, HIPAA, and internal security standards. Implementing Snowflake Data Masking reduces insider risk, limits data exposure, and enforces least-privilege access.

Protect your database before the next 2 a.m. query leaves you exposed. See how easy it is to set up, preview, and manage Snowflake Data Masking live at hoop.dev in minutes.