Current blockchain hot topics in research I'm looking for a research project for my master thesis in software engineering and computer science and i'm willing to research the blockchain technology. What are the current open issues and/or hot topics regard blockchains?

EDIT: I can see my question is way too generic, i just wanted to specify i read about 20 papers on the topic and i'm more concerned about the dencentralization aspect of it.
I think it's scalability. The cost to generate a block is getting more and more expensive. Couple months ago, CryptoKitties caused Ethereum network congestion due to the surge of transactions. For real world application, I think blockchain must be able to handle high volume of transaction. This can be achieved by reducing the cost to generate a block. AFAIK, some blockchains are developing proof-of-stake algorithms replace the old proof-of-work one.

You may interested in Ouroboros proof-of-stake algorithm, which is implemented by Cardano. Ethereum is also working on their own implementation - Casper