Andrea Allred has been checking out Dynamic Data Masking in SQL Server 2016:
This is a great time to talk about the different masking functions and what they do. The four types in 2016 are Default, Email, Random and Custom String.
Default – For numeric and binary it will show a “0” For a date it will show 01/01/1900 and for strings it will show xxxx’s (more or less depending on the size of the field).
Email – It will expose the first letter of the email address and the suffix at the end of the email (.com, .net, .edu etc.) For example Batgirl@DC.com would now be bxxx@xxxx.com.
Random – Number randomly generated between a set range. Kind of like the game, “Pick a number between 1 and 10” but for SQL.
Custom String – Lets you get creative with how much you show or cover and what you use to cover (not stuck with just xxxx’s).
It’s not really a security feature, but it could be useful for protecting sensitive data from snoopers glancing over the shoulder.