Masking is the technique of showing masked data to users who do not have access to some data. This can be seen as hiding personal data, be it financial or health-related information, from those who are not authorized to see it. Masking methods can be different. The following diagram represents one of the Data Masking techniques where you hide Employee Salary with simple XXXX substitution:
Another common masking method is substituting the masked column with random replacement. In this table, Employee Salary is replaced by random salary numbers. The following diagram shows the Data Masking By Random Substitution:
The following diagram shows one of the other common masking techniques using encryption:
