Amazon Redshift already supports role-based access control, row-level security, and column-level security to enable organizations to enforce fine-grained security on Redshift data. Amazon Redshift now extends these security features by supporting Dynamic Data Masking (DDM) that allows you to simplify the process of protecting sensitive data in your Amazon Redshift data warehouse. With Dynamic data masking, you control access to your data through SQL based masking policies that determine how Redshift returns sensitive data to the user at query time.
Source:: Amazon AWS