Encryption on RDDs or in-memory/cache on Apache Spark

I am currently working on the latest version of Apache Spark (1.4.1), pre-built package for Hadoop 2.6+.

Is there any feature in Spark/Hadoop to encrypt RDDs or in-memory/cache (similarly to Altibase's HDB: http://altibase.com/in-memory-database-computing-solutions/security/) when running applications in Spark? Or is there an external library/framework which could be used to encrypt RDDs or in-memory/cache in Spark?

I discovered it is possible to encrypt the data, and encapsulate it into RDD. However, I feel this affects Spark's fast data processing as it is slower to encrypt the data, and then encapsulate it to RDD. Encryption and storing data should be done parallel.