MySQL Replication ignore few columns
Replicate it!  Else you won't be able to failover to a Slave if the Master dies.  Deal with access control in some of the following ways:


Use GRANT to restrict what each user can see.
Use VIEWs to avoid showing the sensitive columns.
Segregate the sensitive columns into other tables (vertical partitioning), so that the GRANT applies to tables instead of columns and VIEWs aren't needed.