Once considered a munition, encryption is now a bedrock of modern life. From its emergence from the State during the ‘crypto-wars’ of the 1970s, to its mass commodification after the revelations of Edward Snowden in 2014, it is now used by over three billion people around the world. There is strong, unsurprising evidence that encryption is discussed, taught, used and developed by terrorist groups, provoking a rising complaint from law enforcement that the world is ‘going dark’. This article looks at cases of terrorists using encryption, and whether it has caused a gap to open between the legal privilege to intercept communications and the technical ability to actually do so. It brings together the evidence for the impact this has for law enforcement and for the interventions – old and new – that have been suggested in order to prevent terrorists disappearing into the dark online places that the law cannot reach.
