The TDE tablespace encryption functionality can be used to encrypt the tablespace where all the data is stored from an EBS application. As TDE is transparent to application, rewriting the code is not required. Any authorized user can access the encrypted data without any issue.
This blog discusses setting up Transparent Data Encryption (TDE) column-level encryption in Oracle® E-Business Suite® (EBS) R12 environment. You can set up column-level encryption on single-column or multiple-column tables, depending on the user requirement.