Tasks > Masking rules > Substitution masking
  

Substitution masking

Substitution masking replaces a column of data with similar but unrelated data from a dictionary.
The masking task provides dictionaries that contain sample data for substitution masking. When you configure substitution masking, select the dictionary that contains the type of substitute values that you need. The masking task performs a lookup on the dictionary that you choose and replaces source data with data from the dictionary.
You can substitute data with repeatable or non-repeatable values. When you choose repeatable values, you must configure a seed value to substitute data with deterministic results.

Substitution masking parameters

To perform substitution masking, you can select one of the dictionaries that the masking task provides.
The following table describes the parameters that you can configure for substitution masking:
Parameter
Description
Repeatable
Returns the same masked value when you run a task multiple times or when you generate masked values for a field that is in multiple tables.
Seed Value
A starting number to create repeatable output. Enter a number from 1 through 999. Default seed value is 190. You can enter the seed value as a parameter.
Optimize Dictionary Usage
Increases the usage of masked values from the dictionary. Available if you choose the Repeatable option. The property is not applicable if you enable unique substitution.
Is Unique
Applicable for repeatable substitution. Replaces the target column with unique dictionary values for every unique source column value. If there are more unique values in the source than in the dictionary file, the data masking operation fails. Default is nonunique substitution.
Preprocessing Expression
Configure an expression in the rule to convert characters before the masking rule runs. For example, you might want to convert all characters to the same case before masking.
Postprocessing Expression
Configure an expression in the rule to convert characters in the masked output before the data is copied to the target.