In early 2017 Clifton Collins, an Irish drug dealer, had a dilemma: where to hide the codes of his illicit €55m (£46m) bitcoin fortune.
His solution was to print them on to an A4 piece of paper and stash it in the aluminium cap of a fishing rod case kept at his rented home in Farnaught, Cornamona, County Galway. It seemed a good idea at the time.
Then three things happened.
