The world is full of big figures, but this one is more shocking than most. $600bn (£483bn) is lost every year from global trade as a result of “maritime fraud” – when goods go walkabout from ships during transactions. And this is just one tiny part of the global business of trade. Add it all up, and there are likely trillions of dollars lost to fraud each year. A coalition of companies, coders and charities believe they have a solution: the blockchain.