Hadoop security has improved with additions such as HDFS ACLs, Hive column-level ACLs, HBase cell-level ACLs, and Knox for perimeter security. Data encryption has also been enhanced, with support for encrypting data in transit using SSL and data at rest through file encryption or the upcoming native HDFS encryption. Authentication is provided by Kerberos/AD with token-based authorization, and auditing tracks who accessed what data.