How to setup encryption on a column that joins two tables in two different databases

What is the best method to encrypt a column that exists in two  tables (BUID)  in two different database on a 2012 server,   at the end should be able to join on the encrypted columns between two tables across databases.

use testdb1
create table table1
(BUID number(10),
ACCOUNT_BALANCE Money)

use testdb2

Create table table2
(BUID number(10),
CUSTOMER_FNAME varchar2(30),
CUSTOMER_LNAME varchar2(30))

basically want to encrypt the BUID in both tables and be able to crate a view  that joins across two databases.

create view vw_cust_balance
as
select
a.buid ,
a.account_balance
b.customer_fname,
b.customer_lname
        from testdb1..table1 a inner join testdb2..table2 b
on a.buid = b.buid

Can someone point me to a resource or example that resolves situation above.