Create IAM groups for each team and manage permissions at the group level. Employ server-side encryption and Object Versioning by Google Cloud Storage. Configure cloud monitoring tools to alert on anomalous data access patterns.

Set individual permissions for each team and apply access control lists (ACLs) to each bucket and file. Enforce TLS encryption for file transfers. Enable Object Versioning and Cloud Audit Logs for the storage buckets.

Use predefined IAM roles tailored to each team's access needs, such as Storage Object Viewer and Storage Object User. Utilize customer-supplied encryption keys (CSEK) and enforce TLS encryption. Turn on both Object Versioning and Cloud Audit Logs for the storage buckets.

Assign IAM permissions for all teams at the object level. Implement third-party software to encrypt data at rest. Track data access by using network logs.