When you set the a character as a source filter character, the character is masked every time it occurs in the source data. The position of the characters in the source string does not matter, and you can configure any number of characters. If you do not configure source filter characters, the masking replaces all the source characters in the field.

The source filter are case sensitive. The

masking

task does not always return unique data if the number of source string characters is fewer than the number of result string characters.