The excellent investigation by Stuart Ramsay, Sky’s chief correspondent, into Islamic State, shows their open and closed approach to technology.
Open, because they push their propaganda and highly produced videos out through very public channels: Twitter, YouTube and JustPaste.it.
The group has a huge and co-ordinated social media presence, as Sky News first reported last summer.
That raises the group’s profile and fires the frustrated imaginations of young people previously unradicalised.
Closed, because when that person decides to go a step further, they are invited off the open web, and on to encrypted messaging services.
From plain sight into dark corners.
That creates a problem for security services, who say they can’t track chats on encrypted messaging services.
They include WhatsApp, the most popular messaging app in the world with more than 800 million users.
David Cameron has asked: “In our country, do we want to allow a means of communication between people which we cannot read?”
In another speech he added: “We just want to ensure that terrorists do not have a safe space in which to communicate.”
The so-called Snooper’s Charter, or Investigatory Powers Bill, is due to be presented by Theresa May this autumn and is expected to address encryption.
The problem is that encryption doesn’t give just terrorists a safe space in which to communicate.