There are two types of encryptions in Hadoop. One is for encrypting data that is transferred over the network. That is called data in transit encryption. Another is for encrypting data that is stored on disks, which is called data at rest encryption. We will look at both of these types of encryption techniques in the following sections.
To understand in transit encryption of any Hadoop cluster, you need to understand how different components are communicating with each other. By how, we mean what kind of network protocol they are using. Enabling encryption over the network depends upon what kind of communication protocol is being used for communication.
We can think of Hadoop cluster components using three different types of protocols, namely RPC, TCP/IP, and HTTP. RPC is used for network communication of MapReduce programming, JobTracker communication, TaskTracker communication, and NameNode communication. The TCP/IP protocol is used for communication...