The US government has decided not to call for new legislation to force tech companies to decode the encrypted communications of their customers - for now at least.
Police and intelligence agencies have become increasingly concerned about the use of end-to-end encrypted communications services by criminals because it is all but impossible to decode the conversations.
With more traditional methods of communication there is usually a way for the service provider to allow police - with a warrant - access to the data. But end-to-end encryption means the only place the message is unscrambled is on the smartphone itself.
"Changing forms of internet communication and the use of encryption are posing real challenges to the FBI's ability to fulfill its public safety and national security missions. This [is a] real and growing gap," said FBI director James Comey in a written statement to the Senate's Homeland Security and Governmental Affairs Committee.
Comey told the committee that terrorists are using social networks to find recruits and then switching to end-to-end encrypted networks to continue their interactions.
"They will move them off of Twitter, where with lawful process we can see the communications, and move them to an end-to-end mobile messaging app which is end-to-end encrypted. So the needle we may have found disappears on us once it becomes most dangerous... we cannot see what is being said between that ISIL recruiter and someone who would kill where they are," he warned.
Comey said the issue with encryption was a clash between the need for safety and security on the internet and public safety. "Those two values we hold dear are crashing into each other. I don't know what the answer is," he said.
The use of strong encryption is also key to banking and ecommerce and critics argue that giving law enforcement a back-door into such systems would undermine the security of everyone.
Privacy campaigners also argue that the use of encrypted communications is a vital lifeline for those living under many regimes around the world: others still argue that revelations such as those by Edward Snowden show that intelligence agencies already have far too much access to the apparently private communications of the public.
Comey said the US government will not call for new laws in this area: "The administration has decided not to seek a legislative remedy now but that it makes sense to continue the conversations we are having that are very productive," he said. According to the Washington Post that decision was made in a cabinet meeting on 1 October.
In contrast, the government in the UK has several times suggested that it wants to pass legislation so that it can gain access to such communications: precisely how it would do that is not clear.
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