VALIDATE RMAN BACKUP

to validate all database files and
archived redo log files for physical and logical corruption:

RMAN> BACKUP VALIDATE CHECK LOGICAL DATABASE ARCHIVELOG ALL;

You can also use the VALIDATE command to individual data blocks:

RMAN> VALIDATE DATAFILE 4 BLOCK 10 TO 13;

You can also validate backup sets:

RMAN>VALIDATE BACKUPSET 3;