The goal of encryption is to ensure that only authorized users can view, use, or contribute to a data set. These security controls add another layer of protection against potential threats by end-users, administrators, and other malicious actors on the network. Data protection can be applied at a number of levels within Hadoop:
OS Filesystem-level - Encryption can be applied at the Linux operating system filesystem level to cover all files in a volume. An example of this approach is Cloudera Navigator Encrypt (formerly Gazzang zNcrypt) which is available for Cloudera customers licensed for Cloudera Navigator. Navigator Encrypt operates at the Linux volume level, so it can encrypt cluster data inside and outside HDFS, such as temp/spill files, configuration files and metadata databases (to be used only for data related to a CDH cluster). Navigator Encrypt must be used with Cloudera Navigator Key Trustee Server (formerly Gazzang zTrustee).
Network-level - Encryption can be applied to encrypt data just before it gets sent across a network and to decrypt it just after receipt. In Hadoop, this means coverage for data sent from client user interfaces as well as service-to-service communication like remote procedure calls (RPCs). This protection uses industry-standard protocols such as TLS/SSL.
DFS-level - Encryption applied by the HDFS client software. HDFS Transparent Encryption operates at the HDFS folder level, allowing you to encrypt some folders and leave others unencrypted. HDFS transparent encryption cannot encrypt any data outside HDFS. To ensure reliable key storage (so that data is not lost), use Cloudera Navigator Key Trustee Server; the default Java keystore can be used for test purposes.   _{Your Comment}