 Let me tell you a short story about a little fellow called Jacob. Since he could remember, Jacob always wanted to get a blue cat, but his parents were always finding ways to not get it for him. So, one Christmas, he figured out a way to finally get his dream pet. He would send his wish to Santa. Oh, how excited he was when he wrote the letter! Jacob was too young to take the letter to the post office by himself, so the next morning, he had to ask his dad to do it for him. You could say that his dad was the middleman between Jacob and Santa. He never imagined that on his way to the post office, his dad would open the letter, read it and replace the blue cat on the list with a brand new pair of socks. The letter was posted to the North Pole to Santa and the Elves. When they received it, they started working right away, making Jacob skip. So, that year, Jacob received an adorable pair of socks. But next Christmas, Jacob decided to use the blockchain. Jacob wrote exactly the same letter, but instead of giving it to his mum or dad to deliver, he directly uploaded it to the North Pole blockchain. The North Pole blockchain is made up of a lot of computers connected to one another through the internet that all store a copy of everyone's Christmas list. The network is being monitored at the same time by all the Elves, Santa himself and even people like Jacob's parents. Every time a new letter is received, it is saved onto every individual computer so everyone has the exact same copy. As the blockchain is an open network, everyone can see all the letters, even though it's impossible to know to whom each one belongs to. But when Jacob's parents saw that there was a letter asking for a blue cat, it wasn't hard for them to know that it was from Jacob. So once again, they changed it, this time for a cookbook. But as every other node had a copy of Jacob's real letter, the change was spotted and the computer trying to make the change was cut off from the network, meaning Jacob's real letter remained unchanged. So guess what Jacob received that year for Christmas?