Key Concepts and Architecture
HDFS must be integrated with an external enterprise-level keystore. The Hadoop Key Management server serves as a proxy between HDFS clients and the keystore. The keystore can be either Ranger KMS or a support Hardware Security Module.
HDFS transparent encryption involves the creation of an encryption zone, which is a directory in HDFS whose contents will be automatically encrypted on write and decrypted on read. Each encryption zone is associated with a key (EZ Key) specified by the key administrator when the zone is created. The EZ keys are stored on the external keystore.