David Rowley is a criminal consultant who will get others to do his dirty work.
He will act charming and knowledgeable in tech then try to recruit you into committing cyber crimes related to cryptocurrency such as Bitcoin.
He is often at startup events and programming events such as hack-a-thons or cooperations etc
Trying to convince you to install Ransomeware on places such as Hospital computers to extort them for Bitcoins first of all puts lives at risk and you risk going to jail. He wants to come in as the saint who is a consultant and would not take any of the risks of committing crimes seems like a bad idea.
I would suggest not working with him unless you plan on going to jail and putting lives at risk.