Two British intelligence officials have proposed what they see as a potential solution to a key challenge facing law enforcement agencies — an inability to intercept encrypted group calls and messages through services such as WhatsApp and Signal.

Their idea: Add law enforcement as a “silent” user to the chat or call.

The notion had been discussed privately by Obama administration officials, but until now has never been advanced publicly by a government.

Ian Levy and Crispin Robinson of GCHQ — the British equivalent of the National Security Agency — included the proposal in a paper published last week that offered a set of principles aimed at lowering the temperature of the often-heated debate over how to access digital evidence protected by strong encryption. 

The debate has been fueled by the rise of “end-to-end” encrypted apps such as Signal and default encryption on devices such as iPhones. It has simmered for about a decade, occasionally boiling over — as in 2016 when the FBI and Apple battled over access to a terrorist’s locked iPhone.