A column configured for key masking returns deterministic masked data each time the source value and seed value are the same. The Data Masking transformation returns unique values for the column.
When you configure a column for key masking, the Data Masking transformation creates a seed value for the column. You can change the seed value to produce repeatable data between different Data Masking transformations. For example, configure key masking to enforce referential integrity. Use the same seed value to mask a primary key in a table and the foreign key value in another table.
You can define masking rules that affect the format of data that the Data Masking transformation returns. Mask string and numeric values with key masking.