Taking on the encryption dilemma
6 March 2015 Last updated at 23:32 GMT
Prime Minister David Cameron believes it is unacceptable that some private communications cannot be accessed by governments thanks to encryption technology.
Phil Zimmerman, referred to by many as the "father of encryption" takes a very different view.
Newsnight's David Grossman travelled to Mobile World Congress in Barcelona to hear about the growing dilemma surrounding privacy and security.