How to get an up to date PhD title in Cloud Computing Security?
You have a couple of options, I hope. One is choosing a new topic that your supervisor is more familiar with. He or she is the one to help you with that, so you need to have a discussion about it. 

However, while your supervisor isn't familiar with the topic you have, he should be familiar with how to do research and to get quickly to the edge of the known world in any given (similar) field. So he may be able to help you find the resources you need and even respond intelligently to your questions and concerns. The only thing that he can't help you with is specific topical questions (facts and techniques). But he can help you find the places in which you can learn that. 

Even if he were more up to date in the field, you would still need to read a lot of papers and work to understand them and the remaining work to be done. 

At some point every doctoral student needs to surpass the understanding of their professor. That doesn't mean the professor is of no use anymore, it is just the specific topic that you are then able to teach them, rather than the other way round.