The game If you listen very carefully during the first 4 cards (or use the cheat sheet) you will get an advantage on the last 5 cards

Transcription

1 The blockchain game GAMEMASTER NOTES Time: 10 minutes The game: up to 9 info/question cards + a short test with 7 questions Reward: The game If you listen very carefully during the first 4 cards (or use the cheat sheet) you will get an advantage on the last 5 cards The story When you make a donation with your hard earned money, you want it to make a real difference. But you ll have to accept, that 25% or more will be used for administrative costs and you ll need to trust, that when reaching its destination, your donation will be spend wisely. But what if the overhead was only 0,001%, and that you would get your money back, if the receiver did not fulfill the agreed goals? Card #1 nodes, miners and POW Before you read card explain: 1. what a block is in the ledger and 2. what we put into each block in our story, and 3. why do you want to make blocks? Card #2 distributed ledgers and genesisblock After card: illustrate how ledgers must be alike Card #3-4 Read the card Card #5 - #9 Read the card The gamemaster counts to measure 7 sec. Download your own copy ot the game: kea.dk/blockchain You ll also need 1. 2 sets of Tricky fingers ( 2. Some LEGO ( dice

2 #1 Proof of work (POW) A node is any computer that is connected to our blockchain. Miners are nodes who fight for the right to build the next block. It is random which miner gets the right (and reward) to build the next block. With POW the likelyhood of winning is proportional to the amount of computerpower you have. Mining rigs use a lot of energy and is therefore often situated where eletricity is cheap (Iceland, China, Hungary). Here the mining rig is represented by: Before we begin to make a blockchain TURN this card to see which miningrig is the fastest right now. #2 Distributed ledger & the genesis block A ledger is a chain of blocks, ordered by the time they were made. A node/miner must support the network by keeping a copy of the ledger. Thus the ledgers are called distributed. ledger When in doubt the majority (51%) wins. The genesis block is the first block in our ledger. All ledgers must look the same at all times. genesis block Lets start up a blockchain for charity. TURN this card to see, which miner will win the right of the genesis block? #3 Hash The connections between each block is made with a hash. If someone wants to tamper with the ledger, they have to change all hashes in all of the ledgers, and each change has a delay (up to one hour) A hash is an encrypted piece of text of a certain length, made from a combination of: 1. the data in the block 2. a time stamp 3. the previous block s hash A new donation of has been added to the blockchain. Who gets to?

3 #4 Smart contracts Just like normal contracts, but they are digital protocols programmed into the blockchain. In our charity case, a smart contract could be an agrement stating that, when a total of is collected, and the lifeboats and blankets are delivered, the money/a payment will be released to the producer. A new donation of has been added to the blockchain. Who gets to? #7 Why do we need distributed ledgers? 1. to save computer power 2. To make a (often transparent) tamper proof system the blockchain right number. 3. in order to let a centralized entity control the data in Everyone who answers this question correct gets a #6 What is a miner? 1. the same as a node 2. a node that makes blocks right number. 3. someone trying to cheat the system Everyone who answers this question correct gets a

4 #5 What is the content of a block? 1. some data and a timestamp right answer. 2. a hash, a timestamp and some data 3. some data, a hash, a hash of the previous block and a timestamp Everyone who answers this question correct, gets a #8 What does the hashes do in the blockchain? 1. a hash makes a connection between the blocks. This makes tampering with ledgers very hard 2. a hash is the data that goes into the blockchain encrypted way of writing the timestamp of the block right answer. 3. the hash is an Everyone who answers this question correct, gets a #9 What is a smart contract? 1. a smart contract is digital and executes automatically when the requeriments are fulfilled 2. a smart contract, is a contract written in a very easy to understand language 3. smart contracts are fully compliant with all traditional legal systems in all contries right answer. Everyone who answers this question correct, gets a

5 How to play: Test your knowledge Each player choose a color. For each turn: 1. A player reads the first card. 2. All players try to solve the puzzle on the back 3. All players get a lego block in the color of the winner, and place it on top of their ledger After the game: Turn the card and test your knowledge

6 A miner A block A ledger Data Timestamp This blocks hash Previous blocks hash The mining rig (the computer power) The story Blockchain - Charity Case When you make a donation with your hard earned money, you want it to make a real difference. But you ll have to accept, that 25% or more will be used for administrative costs and you ll need to trust, that when reaching its destination, your donation will be spend wisely. But what if the overhead was only 0,001%, and that you would get your money back, if the receiver did not fulfill the agreed goals? How to play: Each player choose a color. For each turn: 1. A player reads the first card. 2. All players try to solve the puzzle on the back 3. All players get a lego block in the color of the winner, and place in on top of their ledger After the game: Test your knowledge

7 Blockchain Cheat sheet: Download the game as pdf at kea.dk/blockchain A node A node is any computer that is connected to the blockchain. A node must support (help secure) the network by keeping a copy of the ledger Miners are those nodes that fight for the right (and the reward) to create the next block Mining Rig is a lot of computerpower set up for mining A block contains 4 things: 1. a hash from the previous block 2. some data 3. a time stamp 4. a hash that is unique for the block itselv The unique hash is made on basis of the first 3 things Genesis block is the first block in a blockchain ledger The blockchain ledger is a series of blocks in order of their creation Can you change your ledger? If you try to change the content of a block, you will have to change the hash as well, and all subsequent hashes in the complete chain, which is very time comsuming (see hashes). Afterwards you will have to change the ledgers of all other nodes, to keep the system in sync. That is practically impossible, hence the system is very safe. Distributed & decentralized our ledgers are distributed to all nodes all over the world. Not only one centralised place. Hash The connections between each block is made with a HASH. A hash is an encrypted piece of characters and numbers of a certain length, made from a combination of: - the data in the block - a time stamp - the previous blocks hash If someone wants to tamper with the ledger, they have to change all subsequent hashes in all of the ledgers, and solve the POW-puzzle of each (takes up to a year) Proof of Work (PoW) In some blockchains consensus (who gets to ) is choosen by the proof of work. In POW it is random who makes the next block, but the likelihood of winning (and get the reward) is proportional to the amount of computerpower you have. It takes a lot of energy, and is therefore often situated in Iceland or China, where electricity is cheap. Proof of Stake (PoS) is a type of algorithm by which a cryptocurrency blockchain network aims to achieve distributed consensus. In PoS-based cryptocurrencies, the creator of the next block is chosen via various combinations of random selection and wealth or age (i.e., the stake). It uses less energy than PoW. A smart contract is a computer protocol intended to digitally facilitate, verify, and enforce the negotiation or performance of an agreement. Smart contracts allow the performance of credible transactions without third parties. These transactions are trackable and irreversible. Proponents of smart contracts claim that many kinds of contractual clauses/agreements may be made partially or fully self-executing, self-enforcing, or both. The aim of smart contracts is to provide security, that is superior to traditional contract law and reduce other transaction costs associated with contracting. Various blockchain platforms have implemented types of smart contracts.