Transparent Data Encryption

Column Encryption: Four easy steps

Setup Wallet and Master Key	Identify columns with sensitive data	Review constraints	Encrypt existing and new data

The following data types can be encrypted using TDE:

  varchar2                     nvarchar2
  number                       date
  binary_float                 binary_double
  timestamp                    raw
  char                         nchar

Each table has it's own encryption key (which is stored in the database data dictionary and encrypted with the external master key). Encrypted columns can no longer be used as foreign keys.

To maintain performance, TDE column encryption allows indexes for equality searches:

  SQL> select last_name from customers where credit_card = 4716082825579654;

to be built over encrypted columns in the base table. Other indexes (for range scans) are not suppurted.