class: center, middle # PechaKucha: 20 answers to the question "What is Bitcoin?" jaume at satoshi dot cat (Hit the spacebar or the arrow keys to move to the next slide) CC-BY Thanks to BCT users: remotemass, franky1, logger --- # Hobby * There is no limit to the amount of time you can waste when you get into Bitcoin * It can be highly addictive. It can completely take over your life. Better take it easy. --- # P2P Network * Bitcoin is a P2P internet network, just like bittorrent. * The nodes connect to each other to exchange information. * Resilient. Difficult to censor. --- # Community * It is a community-driven project. * Some smart guys designing the architecture in public forums. * Everyone can participate: code, mine, offer services, teach, or just be a fan. --- # Currency * In some ways, it is like money. * Money that you can use on the internet. * You can buy stuff, pay for services and make donations. * A global internet currency that you can change for local currencies. --- # Internet technology * Just like email, IRC or the web, Bitcoin exists in the internet. * It is available wherever there is internet. --- # Protocol * There is a set of rules or *protocol* for those that want to be part of the game. * If you don't follow the rules, you are not in Bitcoin. * The rules are set and enforced by the community in a somewhat meritocratic way. --- # Software * Bitcoin is free libre open source software. * You can utilise existing code to make an alternative coin. * You can audit the code and contribute. --- # Consensuated Distributed Database * All the full nodes share all the transactions of the history of Bitcoin. * They all agree in the same history. * Consensus is reached by voting with *work*. --- # A Blockchain * The transactions are organized in blocks. * The blocks are organized in a chain. * A new block is added every 10 minutes approximately. --- # A mining lottery * The miner that finds the block is rewarded with coins. * It is a lottery in which the chances of winning are proportional to the *hashrate* (work) of the miner. * The miners keep the network secure with their work. --- # A coin generation algorithm * The supply of money is known by everyone in advance. * Currently 25 new fresh coins are generated every 10 minutes. * The coin generation rate halves every four years. * Some 21,000,000 coins will be generated in total. --- # A decentralized economy * There is no central entity that controls Bitcoin. * The control is distributed and in the hands of the community. * It is our money. And we control it. --- # Payment method * It is a payment method that cannot be censored. * I can send money to Iran or to WikiLeaks, no matter what goverments or banks say. No one can stop me. * You don't need a bank account or passport. No paperwork or registration. * Just internet connections. Even robots can have bitcoins and make payments. * Non-reversible. When a payment goes into the blockchain, there is no way to take it out of there. --- # A transaction graph * The outputs of a transaction are the inputs of another transactions. * It is possible to follow the money and make connections as all the information is public. * The Bitcoin addresses pariticipating in the transactions are pseudonymous. --- # A secure time-stamping system * We know when each transaction occurred. * The depth in the blockchain reveals the order in which all the transactions have occurred. * You can use it for other stuff, such as to prove that you did your homework in time. --- # Public-Private key pairs * Bitcoin uses well known cryptography * Elliptic Curve Cryptography is used for key generation. * Transactions send money to public keys and private keys are needed to spend those outputs. --- # Market roller coaster * Bitcoin is traded for other currencies in markets. * The prices change quite a bit because other currencies are not very stable. * The price of the dollar dropped some 98% compared to bitcoin in 2013. --- # Original paper * The original paper and the first implementation were produced by Satoshi Nakamoto. * Satoshi chose to remain anonymous. --- # Ongoing work * Bitcoin is continuously evolving. * There are some open challenges such as the growing size of the blockchain. --- # Experiment * Bitcoin is an experiment and no one knows how it will end. * So far it has kind of worked for some years. * Join us and be part of it!