Oracle data redaction -Partial

Hello,

we are implementing a oracle data redaction partial for column ssn in our test environement, we created a new policy to redact ssn column but the output is not showing the proper result.

SQL> BEGIN
DBMS_REDACT.ADD_POLICY(
  2    3  object_schema => 'hr',
  4  object_name => 'employees',
  5  column_name => 'ssn',
  6  policy_name => 'redact_cust_ssn',
  7  function_type => DBMS_REDACT.PARTIAL,
  8  function_parameters => DBMS_REDACT.REDACT_US_SSN_F5,
  9  expression => '1=1',
10  policy_description => 'Partially redacts 1st 5 digits in SS numbers',
11  column_description => 'ssn contains Social Security numbers');
12  END;
13  /

PL/SQL procedure successfully completed.

Output

=====

SQL> select ssn from hr.employees;

SSN