Very good talk by Mozilla's Tim Taubert on the Web Crypto api. Not only does he present the information clearly but he also shows the best example of the need to use Promises in Javascript I've seen up to now. The security information he explains now can be implemented using crypto libraries at the moment but in the coming year we'll be able to rely on the browser so that we do not have to fall on javascript so much which can be easily viewed using dev tools or other simple means.