Which two features does Kerberos security add to a Hadoop cluster?
A.
User authentication on all remote procedure calls (RPCs)
B.
Root access to the cluster for users hdfs and mapred but non-root access for clients
C.
Authentication for user access to the cluster against a central server
D.
Encryption for data during transfer between the Mappers and Reducers
E.
Encryption for data on disk (“at rest”)