First of all, thank you so much for this series. It really helped me to grasp this new and confusing idea of blockchain. Watching this particular video, I cant help but wonder if private data that I dont want to open to the public can be locked in a wallet. I hear that blockchain is a huge "open" DB and this openness makes me feel uncomfortable with services that claim to have implemented blockchain in financial and other private stuff that i do not want to share with the public. Could you explain more on this openness quality that blockchain has and how some info can be kept private in blockchain system? Thank you ! :)