This encryption process works so that users who take data by way of database backup. This encryption works when the user restore the database on another server it will fail because it does not have a wallet that has been created. For more details follow these steps :
Edit sqlnet.ora ,First a wallet needs to be created that can store the encryption key . To setup TDE the location for the wallet needs to be set, directory sqlnet.ora : $ORACLE_HOME/network/admin/. Create directory encryption_wallet in your database server. example directory : /u01/app/oracle/admin/diarycoding/
Create Directory in example directory
MKDIR encryption_wallet
Edit sqlnet.ora
ENCRYPTION_WALLET_LOCATION= (SOURCE=(METHOD=FILE)(METHOD_DATA= (DIRECTORY=/u01/app/oracle/admin/diarycoding/encryption_wallet/)))