How to replicate MySQL table in different servers?
Start by splitting your confidential info out of the table.  Make a 'parallel' table ('vertical partitioning').  The new table would have the same PRIMARY KEY as the original, so they can easily be JOINed together.

To avoid replicating the new table, either use replicate_ignore_wild=... on the slave or put the table in a different database and use binlog_ignore_db=... on the master.

Or you could let it replicate, but change permissions so that most people do not have even SELECT privilege to that table/database.

That would be a minimal first step toward securing the data.  I say it is only a fist step because if the Master is hacked into or stolen, there is nothing to stop them from getting the confidential info.