Meiri said that the central bank currency use case involves real scale and a solution which requires more than just the Bitcoin blockchain. "We started with coloured coins; assets on top of the Bitcoin blockchain. While it's great for certain things, it's not great for assets that need millions of transactions. A digital version of cash is something that you need to transfer a lot every day, so we cannot work only with the Bitcoin blockchain. He said: "We are working with something that will basically connect the public blockchain, which for me is only Bitcoin, and private network that a central bank or a city would be able to run. "We have developed something that I cannot say a lot about yet. We are going to have something published about it later on this year. But we connect basically between a private permissioned chain with the Bitcoin blockchain. Meiri said this could impart the sort of security and immutability associated with Bitcoin, while having more freedom to add privacy and AML, KYC to the ledger that the country is going to run. "If you start a network which is permissioned and the central bank knows all the players, but you use the transparency and the immutability of the Bitcoin blockchain, then we get into a very interesting point where you are gaining from both worlds. "You have the private chain which is secure because it's a network, and let's say every now and then all the transactions are being hashed on Bitcoin blockchain." http://www.ibtimes.co.uk/bitcoin-innovator-colu-looks-connect-blockchains-central-bank-cryptocurrencies-1567079