Although network encryption has been provided in the Apache Hadoop platform
for some time (since Hadoop 2.02-alpha/CDH 4.1), at-rest encryption, the
encryption of data stored on persistent storage such as disk, is not. To
meet that requirement in the platform, Cloudera and Intel are working with
the rest of the Hadoop community under the umbrella of Project Rhino — an
effort to bring a comprehensive security framework for data protection to
Hadoop, which also now includes Apache Sentry (incubating) — to implement
at-rest encryption for HDFS (HDFS-6134 and HADOOP-10150).
Looks like I got this wrong: Apache Sentry will become part of Project Rhino.
Original title and link: Project Rhino goal: at-rest encryption for Apache Hadoop