HDFS Encryption delivers transparent end-to-end encryption of data at rest and is an integral part of HDFS. End to end encryption means that the data is only encrypted and decrypted by the client. In other words, data remains encrypted until it reaches the HDFS client.
Each HDFS file is encrypted using an encryption key. To prevent the management of these keys (which can run in the millions) from becoming a performance bottleneck, the encryption key itself is stored in the file metadata. To add another layer of security, the file encryption key is stored in encrypted form, using another “encryption zone key”.
Read on to learn more and to see how it all fits together.