but christopher wylie, the former uk-based cambridge analytica employee-turned whistle-blower said that the core of the company's activities was the access facebook provided. >> so we went from no data to, you know, harvesting all of this -- this data off of facebook and then combining it with all this -- you know, the consumer data sets and voter data sets. so, you know, we had sort of a steve bannon and a billionaire breathing down our necks going, where's the data? where's the algorithms? where's our information weapons? and that's where kogan came along, alexander kogan, the professor at cambridge. >> alexander kogan is the cambridge university researcher who in 2014 developed an app, a facebook personality test called, this is your digital life. 270,000 people voluntarily took the personality test. but what no one who took the test knew is that kogan's app opened the door to all their