With little fanfare, a new technology was invented in 2009 that is probably one of the most impressive of the century. A person known as Satoshi Nakamoto, the inventor of the Bitcoin whose name is quite possibly a pseudonym, was trying to resolve a very well-known problem concerning digital currencies. A digital currency is basically a digital code that is stored on a computer. How can we ensure that the same Bitcoin is not spent several times? The solution to the problem is simple, but also brilliant. Nakamoto proposed that all transactions should be public. If they are public, anybody can check whether a virtual coin has already been spent or not. To achieve this, Nakamoto came up with a system in which various transactions are put together in blocks and these blocks are written in a chain. In English, the chain of blocks is called a “blockchain”.