/bigquery-basics

BigQuery IAM & Security

BigQuery uses Identity and Access Management (IAM) to provide granular access control to its resources. As a security best practice, follow the principle of least privilege: grant only the permissions required to perform a specific action. This includes using the least permissive IAM role at the most granular level—such as the table or view level—that is necessary.

Predefined IAM Roles

For a complete list of predefined roles and detailed usage information, see BigQuery IAM roles.

Service Accounts and Agents

• Default Service Account: BigQuery uses a managed service account (bq-PROJECT_NUMBER@bigquery-encryption.iam.gserviceaccount.com or the more general BigQuery Service Agent service-PROJECT_NUMBER@gcp-sa-bigquery.iam.gserviceaccount.com) for internal operations.

• Service Account Impersonation: Use gcloud config set auth/impersonate_service_account for secure, temporary credential access.

Data Security

• Encryption at Rest: All data is encrypted by default using Google-managed keys. Use Customer-Managed Encryption Keys (CMEK) for greater control.

• VPC Service Controls: Define a service perimeter to prevent data exfiltration.

• Column-Level Security: Use policy tags to restrict access to sensitive columns.

• Row-Level Security: Use row access policies to filter data based on user identity.

• Data Masking: Obscure sensitive data in a table while still permitting authorized users to access surrounding data.

• Audit Logs: Record user activity and system events to enforce data governance policies and identify potential security risks.

• Authorized Views: Allow users to query a view without granting them access to the underlying tables.

For more detailed information, see: BigQuery Security Overview.