Now that the provisions of the EU General Data Protection Regulation (GDPR) have become enforceable since 25 May, the work done by Israel-based startup QEDit to develop the ZeroKnowledge Blockchain has taken on a heightened relevance. The company, whose name is based on the Latin expression quod erat demonstrandum (QED), used in mathematics to sign off on a proof, has come up with a solution, based on the zero-knowledge proof proof principle, that enables people to provide proof of compliance with rules or conditions to financial institutions or other types of company without actually having to share private data. CEO Jonathan Rouach, with whom we met up on his company's stand at the recent Viva Technology event in Paris, set out some concrete use cases for his invention: "If I want to obtain a bank loan, I have to handover my data – i.e. give it to the bank so that they can make their calculations and see whether they can grant me that loan or not. Now however, we're seeing more and more use cases where people don't want to hand over their data; they want to keep it confidential, but they still need carry out a verification process. For example, military chiefs with fighter aircraft want to know whether they need to replace the Thales equipment but they don't want to give Thales their operations data because that's classified, secret information. Now QEDit enables a reliable analysis of the data to be carried out without handing over the data. This is about authenticating the calculations. You send proof instead of sending data", he explained. To illustrate what is known as the 'zero knowledge' concept, Jonathan Rouach takes as an example a story that arose from the children's puzzle book series Where's Wally?. He tells us: "There was this person who went into children's bookshops in Paris distributing copies of the French version of the books – 'Où est Charlie ?'. When children came across the book and couldn't find Charlie-Wally in the picture, they were going crazy. Of course, the bookseller knows the solution to the puzzle but he's not supposed to tell them where it is, he can only prove to them that there actually is a solution. So he takes an envelope that's four times bigger than the book, he makes a hole in the middle and he shows Charlie to the child, because he knows exactly where Charlie is. Then he takes the book out of the envelope again." Rouach underlines that "the child now knows Charlie is actually in the picture. The bookseller has given him or her the proof without giving away the solution." QEDit has set out to integrate the 'zero-knowledge proof' approach into the blockchain and standardise it across all of industry, starting with the banks. Indeed, part of banks' future may well lie in this direction: profiling themselves as a trusted third party working to protect the private data of their customers.Viva Technology event in 2018 for the third year running.