Hi Archana

You might want to consider Big Data Security. This presents a great challenge due to the fact that Big Data can be enabled by existing corporate distributed systems, cloud based systems, or Internet of Things systems, all of which present unique challenges to security. You also might not want to restrict yourself to Hadoop, since there are a host of other options you could look at too. I have attached a list of some research papers on Big Data Security to give you a flavour of what the area is like.

I hope that helps.

Regards

Bob