The personal data such as SSN, bank account numbers etc. are encrypted in the database. If you have the need to decrypt the data in SQL then the encryption key is required for your SQL developers to encrypt the data.
To obtained the encryption key, from the NLS setup under Systems and Encryption Keys, select the key ID from the list and click the retrieve encryption key button on the top left of the menu. If no password has been setup use the password "temppassword".
If the password does not meet Business requirement, can change it accordingly:
