Column encryption - encrypting existing column

It is common case that organizations first create database and later decide that they want to implement encryption. In this recipe, you're going to encrypt an existing column using TDE column encryption.

Getting ready

It is assumed that a keystore is opened and a master key is created.

How to do it...

1. Connect to the database as a user who can read data from the OE.CUSTOMERS table (for example, the oe user):

   $ sqlplus oe
   

2. Select data from column you want to encrypt (for example, cust_email), just to verify that the user can view it.

   

   Figure 18 - A test query

3. Connect to the database as a user who has administer key privilege or SYSKM privilege (for example, maja):

   SQL> connect maja
   

4. Encrypt the cust_email column in the oe.customers table using the default encryption algorithm (AES192) and no salt.

   

   Figure 19 - Encrypting an existing column, which has an index

5. Execute steps 1 and 2 again to verify that there is no change in the way user/application views...