You can protect your backups with rman encryption. You have three ways to rman backup encryption. You can use wallet, password or dual mode. I will tell you password protection.
Configure RMAN Backups With Password Protection
rman target /
RMAN> set encryption on identified by ‘yourpassword’ only;
You can backup with backup database command. Do not need to change any backup script.
You can change encryption algorithm on RMAN Configuration.
Show Encryption Algorithm
SQL> select algorithm_id, algorithm_name, algorithm_description, is_default from v$rman_encryption_algorithms;
Change Encryption Algorithm
RMAN> show encryption algorithm;
RMAN>configure encryption algorithm ‘AES256’;
If you want to restore from encrypt backup, you can use below decrypt backup.
Decrypt RMAN Backup
RMAN> set decryption identified by ‘yourpassword’;