Personal devices and persons

USA President Obana is reported saying (NYT 2016/03/12): “If, technologically, it is possible to make an impenetrable device or system, where the encryption is so strong that there is no key, there is no door at all, then how do we apprehend the child pornographer? How do we disrupt a terrorist plot?”

Anwer with another question: “How do we make a child pornographer or a terrorist talk if he does not want to?”