Disable Access to Encrypted Data
Perhaps a sensitive table is needed only during regular work hours, even though the DBMS runs continually. Disabling encryption and decryption at the end of the work day will prevent unauthorized access during the night shift.
To make the encrypted data inaccessible, disable the passphrase.
To disable the passphrase
Use the MODIFY statement, specifying an empty string for the passphrase:
MODIFY tablename ENCRYPT WITH PASSPHRASE='';
An attempt to access the data will result in the following message:
E_US24BF A query has been issued against a table for which encryption has not been unlocked with the MODIFY statement. This unlock statement must be issued every time the installation is restarted. Please contact your data administrator.