January 29, 2025

What is a Snowflake Masking Policy?

Learn about Snowflake masking policies, a dynamic security feature for protecting sensitive data through role-based access and compliance with regulations.
Dexter Chu
Product Marketing

What is a Snowflake masking policy?

A Snowflake masking policy is an advanced security feature available in the Enterprise Edition or higher of Snowflake. It allows administrators to define and enforce rules to mask or tokenize sensitive data within table columns or views. By applying these policies, organizations can control how sensitive information is displayed to users based on their roles or access levels. This ensures compliance with data protection regulations and enhances overall data security. For example, integrating masking policies with role-based access control in Snowflake ensures that only authorized users can view unmasked data.

The masking policy works dynamically, meaning the data remains unaltered in storage but is transformed on-the-fly when queried. This approach ensures that authorized users can access unmasked data while others see a masked or obfuscated version. Snowflake masking policies are highly customizable, enabling organizations to tailor them to meet specific security requirements.

How are masking policies created in Snowflake?

Creating a masking policy in Snowflake involves defining a set of rules that dictate how data should be masked or transformed. These rules are implemented using the CREATE MASKING POLICY command. Each policy specifies the conditions under which sensitive data is either displayed in its original form or masked. By aligning masking policies with warehouse creation strategies in Snowflake, organizations can improve their overall data governance approach.

The process requires careful planning to ensure that the policy aligns with organizational security standards and regulatory requirements. Below are the key components and syntax for creating a masking policy:

Key components of a masking policy

  • Unique Name: Each masking policy must have a unique name within its schema to avoid conflicts and simplify management.
  • Input Columns and Data Types: The policy specifies the columns and their data types to which it applies, ensuring accurate masking logic.
  • SQL Expression: The logic for masking or transforming data is defined using SQL expressions. These expressions can include conditions, functions, and role checks.
  • Optional Parameters: Additional options such as comments and the EXEMPT_OTHER_POLICIES property provide flexibility in defining the policy.

Example: Creating a masking policy

Here is an example of a simple masking policy that masks email addresses for all users except those with the 'ANALYST' role:


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

In this example, users with the 'ANALYST' role can see the full email address, while others see a masked version represented by asterisks.

How are masking policies applied and managed?

After creating a masking policy, it must be applied to specific columns in tables or views. This ensures that the policy's rules are enforced whenever the data is accessed. For instance, using masking policies with external tables in Snowflake can extend data security to external datasets while maintaining centralized governance.

Applying masking policies

To apply a masking policy to a column, use the ALTER TABLE or ALTER VIEW command. For example:


ALTER TABLE employee
MODIFY COLUMN email
SET MASKING POLICY email_mask;

This command associates the email_mask policy with the email column in the employee table. The policy will now govern how the data in this column is displayed based on user roles.

Managing masking policies

1. Viewing policies

Use the GET_DDL function to view the definition of an existing masking policy.

2. Describing policies

The DESCRIBE MASKING POLICY command provides details about a policy, including its configuration and associated columns.

3. Access control

Proper privileges such as APPLY MASKING POLICY or OWNERSHIP are required to manage masking policies effectively.

What are the access control requirements for masking policies?

Access control is a critical aspect of managing masking policies in Snowflake. Only authorized users should be allowed to create, modify, or apply these policies to ensure data security and compliance with organizational standards.

Privileges required

  • CREATE MASKING POLICY: This privilege is required on the schema where the policy is being created.
  • APPLY MASKING POLICY: This privilege is necessary for applying a masking policy to a table or view column.
  • OWNERSHIP: Users with this privilege can manage all aspects of the policy, including altering or dropping it.

Role-based access control (RBAC)

Implementing RBAC is a best practice for managing masking policies. This involves creating custom roles with specific privileges and assigning them to users based on their responsibilities. For example:

  • Create a Custom Role: Define a role such as MASKING_ADMIN for managing masking policies.
  • Grant Privileges: Assign the necessary privileges to the custom role.
  • Assign Role to Users: Grant the custom role to users responsible for data security and masking policy management.

How does dynamic data masking work in Snowflake?

Dynamic data masking in Snowflake enables real-time protection of sensitive data by applying masking policies to database columns. This feature ensures that data remains unaltered in storage but is transformed dynamically based on the user's role or access level during query execution. For example, combining dynamic masking with Snowflake roles enhances security by tailoring data visibility to user permissions.

Steps to implement dynamic data masking

  1. Grant Privileges: Assign a role with privileges to create and manage masking policies.
  2. Create Masking Policies: Define policies that specify how data should be masked for different roles.
  3. Apply Policies: Use the ALTER TABLE or ALTER VIEW command to associate the policies with specific columns.
  4. Verify Implementation: Test the policies to ensure they function as intended and provide the desired level of data protection.

Example: Dynamic data masking

Here is an example of a masking policy that displays unmasked data for users in the 'PROD_ACCOUNT' account and masked data for others:


CREATE MASKING POLICY mask_sensitive_data
AS (val STRING)
RETURNS STRING ->
CASE
WHEN current_account() = 'PROD_ACCOUNT' THEN val
ELSE 'MASKED'
END;

This policy ensures that only users in the production account can see the full data, while others see a masked version.

What are the benefits and challenges of using Snowflake masking policies?

Snowflake masking policies provide significant advantages for data security, but they also pose challenges that must be addressed for successful implementation.

Benefits

  • Enhanced Security: Masking policies protect sensitive data from unauthorized access, reducing the risk of data breaches.
  • Compliance: They help organizations comply with data protection regulations such as GDPR and HIPAA.
  • Flexibility: Policies can be customized to meet specific security needs, allowing for granular control over data access.
  • Dynamic Masking: Data is masked in real-time, ensuring that users see only the data they are authorized to access.

Challenges

  • Complexity: Designing and managing masking policies can be complex, especially in large organizations with diverse security requirements.
  • Performance Impact: Complex masking logic can affect query performance, particularly for large datasets.
  • Maintenance: Policies must be regularly reviewed and updated to remain effective and aligned with organizational needs.

What is Secoda, and how does it streamline data management?

Secoda is a cutting-edge data management platform designed to centralize and streamline data discovery, lineage tracking, governance, and monitoring across an organization's data stack. By acting as a "second brain" for data teams, Secoda enables users to easily find, understand, and trust their data through features like search, data dictionaries, and lineage visualization. This ultimately improves data collaboration and operational efficiency within teams.

With Secoda, organizations can achieve a single source of truth for their data, making it accessible and understandable for both technical and non-technical users. Its AI-powered tools enhance data understanding and simplify complex data processes, ensuring teams can focus on analysis and decision-making rather than searching for information.

How does Secoda improve data accessibility and collaboration?

Secoda enhances data accessibility and collaboration by providing tools that cater to both technical and non-technical users. Its intuitive interface and natural language search capabilities make it easier for anyone to locate and understand the data they need. Additionally, collaboration features allow teams to document, share, and govern data assets effectively, fostering better teamwork and communication.

Key features that enhance collaboration

  • Data discovery: Users can search for data assets using natural language queries, simplifying the process of finding relevant information.
  • Collaboration tools: Teams can share data insights, document data assets, and align on governance practices seamlessly.
  • Granular access control: Ensures secure and compliant data sharing across the organization.

By leveraging these features, Secoda empowers teams to work together more efficiently, reducing silos and improving data-driven decision-making.

Ready to take your data management to the next level?

Secoda offers a comprehensive solution for organizations looking to improve data accessibility, governance, and collaboration. With its AI-powered insights and intuitive tools, you can streamline your data processes and focus on what truly matters—making impactful decisions. Get started today and experience the difference Secoda can make for your data operations.

  • Quick setup: Implement Secoda with minimal effort and start seeing results immediately.
  • Enhanced efficiency: Spend less time searching for data and more time analyzing it.
  • Long-term benefits: Improve data quality, compliance, and collaboration across your organization.

Keep reading

View all