How do you stop online students cheating?
Imagine taking a university exam in your own home, under the watchful eye of a webcam or with software profiling your keystrokes or your syntax to see whether it really is you answering the questions.
Online university courses have become the Next Big Thing for higher education, particularly in the United States, where millions of students have signed up for courses from some of the most upmarket universities.
But a major stumbling block has been how such digital courses are assessed.
When students are at home how do you know whether they are cheating? How you do know the identity of the person answering the questions?
Jane O'Brien talks to the head of edX, one of the important new online university projects, and hears how such online learning is being used by the US military.