 My name is Tyler. For many years, I was a product manager at companies like Google, and Pinterest, and Reddit. More recently, I've dedicated myself full time to learning about and writing about the many exciting things happening in the world of cryptocurrency. Today, I'd like to help you take your first few steps on that journey by showing you what a cryptocurrency is, how it works, and why so many of us are so excited about them. We'll go over this in three sections. First, what is Bitcoin? Second, what is decentralized finance, or DeFi? And third, how to stay safe in crypto? If you're listening to this talk, you've probably heard of Bitcoin, but you might not be entirely certain what it is. If we pulled someone off the street and asked them to describe Bitcoin, chances are they'd say something like Magic Internet Money. That was a real ad, by the way, that ran on Reddit for many years. Magic Internet Money is honestly not an unreasonable starting point, but I do think we can do better. So let's unpack. First, Bitcoin is a digital currency. But by itself, that's not actually very interesting. To a first approximation, all currency is digital. Your boss probably isn't mailing you paper slips or gold bars. So what's interesting about Bitcoin isn't that it's digital, but that it's trustless and permissionless. Trustless means you can take a payment from me without needing to know or care who I am. Permissionless means no one can stop me from sending you a payment, and no one can stop you from receiving it. That's not true of digital dollars. To move digital dollars, you need the bank's permission, and there are a lot of rules about where and how you're allowed to do that. But there is an example of money that we're all already familiar with from our everyday life that is both trustless and permissionless. Physical cash. Cash is trustless. You don't need to trust me to know that I've given you a dollar because you haven't. Cash is permissionless. No one can stop us from exchanging a dollar if we want to. That's part of why governments are eager to eliminate the use of physical cash. It's much more difficult to control than traditional digital currencies. Bitcoin is the very first digital cash. You can also think of it as digital gold or digital real estate or digital bearer bonds. The important thing is that it's the very first scarce digital asset. When I send you a Bitcoin, I don't have it anymore, and that's never been true of anything digital before. It may not sound like much, but it's actually a really profound revolutionary change. So, how does it work? To be money, you need to guarantee two things. Only you can spend your money, and you can only spend your money once. There are many different types of money, but they all ultimately fall into one of two families, tokens or ledgers. Tokens are objects like cowrie shells or gold coins or $20 bills. Only you can spend your money because only you are physically in possession of it, and you can only spend your money once because once you give it to someone else, you don't have it anymore. Pretty straightforward. Ledgers are records of who owns what, like the money in a bank, which is ultimately just an entry in a database in one of the bank's computers. Only you can spend your money because the bank checks to make sure that it's you, and you can only spend your money once because the bank checks to make sure that you haven't spent it already. So, let's suppose that you tried to double spend the money at a bank, say by writing two checks for the same $20. When the first check reached the bank, they would process it normally, debit your account $20 and clear the check. When the second check arrived, they would see that your account no longer had money in it and bounce the check. Notice that this is ultimately a time stamping problem. Neither check is invalid until we know which check came first, and if the bank, using a ledger, that ultimately decides that. Ledgers are very efficient and have a lot of advantages, but they do have one fatal flaw. Tokens, like cash, are trustless and permissionless. Ledgers are not. You need to trust the bank to keep track of your money, and when you want to spend it, you'll need the bank's permission to do so. So, how does Bitcoin make sure that only you can spend your money, and you can only spend it once? The only you part is relatively easy. Bitcoin are stored in mathematical addresses, made up of pairs of extremely large numbers known as keys. The first, the public key, operates a bit like an email address. Anyone who knows your public key can use it to send money to your address. The second, the private key, operates a bit like a password, and as the name suggests, should never be shared. This type of cryptography is elegant, but it's not especially new. This is the same basic technology that underwrites every password-protected system that we use today. Bitcoin's real innovation is in how it solves the problem of making sure you can only spend your money once, and the answer is both simple and profound. You can only spend your Bitcoin once, because Bitcoins do not exist. There is no object and no piece of data that represents a Bitcoin. There are no Bitcoins on your computer, and there are no Bitcoins on anyone else's. That's because Bitcoins are not a kind of token. Instead, Bitcoin is a type of ledger called the blockchain. Anyone can download the blockchain for themselves and confirm what Bitcoin have moved where, which is what makes Bitcoin trustless. And anyone can join the team of accountants that update the Bitcoin ledger, known as Bitcoin miners, and that's what makes Bitcoin permissionless. You don't need anyone's permission to use Bitcoin, because if no one will process your transaction, then in the worst case scenario, you can become a Bitcoin miner and process your transaction for yourself. But if anyone can become a Bitcoin miner, how can we trust them to update the ledger honestly? That's Satoshi's brilliant invention. Updating the Bitcoin ledger is pointlessly expensive, and then subsidized with Bitcoin. So what do I mean by that? To be eligible to add new blocks to the Bitcoin blockchain, miners must first do a complicated math problem that proves they spent a lot of computational resources finding the answer. Doing that math costs money. You have to buy the computers, the electricity, etc. And then the Bitcoin network pays you back for that effort in Bitcoin itself, some from transaction fees and some from the supply of Bitcoin that hasn't been created yet. Paying Bitcoin miners this way keeps them honest, by forcing them to invest in Bitcoin in order to qualify for the privilege of writing part of the history of the network. Miners are kept honest, because they have provably aligned their financial incentives with the overall network. The math here is simpler than you might think. The Bitcoin white paper is quite readable, and only eight pages long. But the basic idea is, you don't trust the miners to be honest. You only trust them to be greedy. As long as the greedy miners outnumber the active attackers, the ledger will stay defended. Okay, my name is a clever parlor trick. It lets you turn a pile of faceless internet strangers into a perfectly cooperative unit. But why does it matter? Why is being a trustless, permissionless, digital cash exciting? Bitcoin has a handful of very powerful properties for money. First, Bitcoin can't be counterfeited. You can't counterfeit a Bitcoin, because bitcoins don't exist. There's nothing to counterfeit. It would be like trying to counterfeit having a bank account. Bitcoin can't be seized. No one can take your Bitcoin from you. You can lose them, or someone can force you to give them to you. But nothing can take them from you, because there's nothing to take. There's only the ledger on the blockchain, and that can only be updated if they know your private key. Bitcoin can't be censored. Banks have myriad rules about where and how you can spend your money, and some businesses, like marijuana dispensaries or pawn shops, can be entirely de-platformed and not allowed to have a bank account at all. But no one can stop you from buying or selling things with Bitcoin. The network is open 24-7, and you can send any amount of money at any time to any other user on the network. Always. Bitcoin cannot be inflated. It's impossible to create more Bitcoin because there are no Bitcoin. There's only the blockchain ledger, and the ledger does not allow transactions that spend more than your account controls. There's no central authority that can decide to create more Bitcoin, so there will only ever be 21 million. But Bitcoin is more than money. If you've ever heard the phrase, history is written by the winners, you have a sense for how difficult it is to know things about the past with any kind of objective certainty. Our knowledge of the past is imperfect. Some sources are lost, some lie or omit things, others are just biased or mistaken. It's a painstaking effort to understand the past, and it's not always possible. But Bitcoin is different. Since its launch in 2009, Bitcoin has faithfully recorded a perfect history of every transaction ever made. It's a small and narrow piece of history, but it is perhaps the first piece of history we've ever been able to know with objective certainty. We can know with perfect precision and total confidence everything that it has ever recorded. Over time, we'll be able to use that record in more ways to enable more things, and whatever we do with it, we will be able to remember with perfect clarity forever. It's entirely possible that our grandchildren will look back on this time as the dawn of recording history. Bitcoin is the original cryptocurrency, but it didn't take long for people to start copying it, adapting it, and building new things on top of Satoshi's foundational insight about how to trustlessly cooperate. What's happening in crypto right now is a kind of Cambrian explosion. Literally thousands of new projects and technologies have spawned, and new ones are appearing every day. And like the Cambrian explosion, the vast majority of these early experiments will go extinct as the market settles on the most elegant and efficient solutions to the problems people are actually willing to pay to solve. So we won't have time today to cover everything happening in crypto, but I wanted to introduce you to a few of the concepts and communities you might encounter, as at least an introduction to the breadth and complexity of the space. For now, we'll talk briefly about five broad families of crypto technology. By design, Bitcoin is intended to be very conservative, prioritizing security and decentralization above flexibility and feature set. You can basically only do two things with Bitcoin. You can keep it, or you can give it to someone else. There's a little bit of fancy footwork you can do in the limit, but overall it's a pretty lockdown platform. Other cryptocurrencies have made different trade-offs to enable more flexible programs, often called smart contracts, to operate directly on the blockchain itself. Most prominent among these is Ethereum, the number two cryptocurrency by market cap, although there are quite a few competitors in the space. Ethereum is Turing Complete, which means you can run literally any program that you can imagine directly on the Ethereum blockchain. That's powerful, because it allows so much innovation to flourish, but it also has risks. Greater flexibility means greater opportunity for bugs or exploits, which have happened. The smart contracts themselves, also called decentralized applications or DApps, are the programs that run trustlessly on top of a decentralized ledger like Ethereum or Bitcoin. There's a gold rush right now to recreate all the products and markets of traditional finance in a decentralized way, often collectively referred to as decentralized finance, or DEFI for short. These can be decentralized exchanges or lending protocols or prediction markets, or basically any kind of contract that you could imagine in traditional finance, and also many that have never been seen before. The things that are happening in DEFI right now are often truly wild. What you're seeing here is the log of what's called a flash mint, where the developer created eight quintillion dollars and then destroyed them all within a single atomic transaction, briefly making himself the richest person in history by many, many orders of magnitude. Less difficult to imagine, but probably more important in terms of impact on the market today are stablecoins. Stablecoins are tokens that attempt to track the price of traditional government currencies like the dollar, basically allowing you to use dollars but on the blockchain. That's especially important in the world of decentralized finance since lots of real-world economic activity is denominated in USD. Some stablecoins do this algorithmically on a DEFI smart contract, but the largest and most famous stablecoin is Tether, which is much simpler. Tether accepts dollar deposits and gives back Tether tokens to represent those dollars, sort of like poker chips in a casino. This kind of approach is not really a cryptocurrency because it does require trust, the trust that Tether will keep the USD deposit safe and that they won't create new Tether tokens without the equivalent of dollars to back them. In that sense, Tether is more like a bridge between a trusted and trustless world rather than a native crypto asset. Blockchains, as you have probably heard, are expensive, slow, and difficult to scale. They have high fees and long confirmation times. Layer 2 technologies like Lightning on Bitcoin or Plasma on Ethereum are attempts to use the foundation of the blockchain to build a more user and dev-friendly experience on top of it, much the way that the HTTP protocol builds on top of the TCP IP layer. For a more intuitive example, consider paying for drinks on a tablet of bar. You open up a minor account with the bar by giving them a credit card. They keep track of the drinks you order but don't actually charge you yet. Then, at the end of the night, you settle up and close your account. The bar charges you for all of your orders in a single payment. The reason that bars do this is because credit card fees are expensive, so they try to use them as efficiently as they can to enable their business. Layer 2 networks are similar strategies for minimizing the number of fees you need to pay for various transactions. And indeed, the most successful one so far, Lightning, actually does operate loosely like a tab in a bar. Just like with stablecoins, there are different approaches to building Layer 2s that have different trust trade-offs. Some, like Lightning, are purely decentralized. Others, like Liquid Bitcoin, require trusting a federated group of exchanges. But they're all attempts to reduce the transaction costs while still anchoring to the original Layer 1 blockchain. Finally, another family of crypto projects that you've probably heard about are non-fungible tokens, or NFTs. NFTs are digital tokens that represent something unique. That's what non-fungible means, more or less. They can represent ownership of a video game item, or a piece of digital real estate, or, famously, they can be used to represent digital art. Recently, the market for digital art has exploded. What you're looking at here are a handful of crypto punks, one of the earliest NFT projects. Crypto punks are a set of 10,000 NFTs that each represent a unique 24x24 pixel avatar. They were originally released for free to anyone who wanted to claim one. Each of the ones you're looking at now last sold for more than a million dollars. NFTs can be as complex and diverse as any DeFi smart contract, but at the moment, the majority of them have no function other than to represent ownership. They mostly don't let you do anything, which can make them hard to understand. The easiest way to conceptualize owning the NFT for a piece of digital art is like having your name on a plaque next to a work of art you loaned to a museum. It's a very specific kind of bragging rights that attest to either your taste in having identified an influential work of art early or your wealth in having been able to acquire it after it already achieved prominence. NFTs are like technologically advanced certificates of authenticity signed by the original artist. Crypto, as you no doubt have been told, is a very dangerous place. Decentralized money means that no one can stop you from saving or spending, but it also means no one can help you recover it if you lose it, or are the victim of a scam. There's no lost password link, no help desk, no phone line, no one you can sue. Bitcoin and other cryptocurrencies offer freedom, but they demand vigilance. You are the only one who can keep you safe. There's too much for us to go over everything in one video, but as a starting point, here are four simple rules to keep in mind that will help keep you safe and crypto. First, make a plan and stick to it. Bitcoin and other cryptocurrencies are volatile assets. The price swings around wildly, sometimes dropping nearly 50% in a day. Those kind of movements can be stomach-churning, which is why it's critical not to invest more than you can afford to lose. If you've invested more than you can afford to lose, you'll be afraid of losing it, and we don't make good investment decisions when we're afraid. So make a plan ahead of time for how much you want to invest and what your time horizon is, and stick to the plan. It's impossible to predict the Bitcoin market, so don't bother trying to tie in your entry or your exit. Don't buy the dip, don't sell the top. Make a plan, dollar cost averaging over time, and then leave it alone. Nearly everyone who tries to increase their stack by trading ends up losing money. Second, choose your exchange carefully. After you've decided your investment strategy, the next step is deciding which exchange to use to invest. There are obvious differences like which coins are available, how much leverage is offered, and how much disclosure the exchange requires for know-your-customer and anti-money laundering laws. But the most important consideration is what's called counterparty risk. Basically, the risk that the exchange will steal or lose your money. When you store Bitcoin on an exchange, you no longer own Bitcoin. What you own are Bitcoin IOUs. Many Bitcoiners have been disappointed to learn the difference when their exchange was hacked or had a margin collapse and they lost money. The most important consideration when choosing an exchange is not fees, selection, or onboarding rules. It's whether you trust that exchange with your money. Cryptocurrency exchanges are basically banks, so if you wouldn't bank with a company, don't buy or store your Bitcoin with them either. Third, store your coins carefully. Bitcoin stored on your phone is like cash in your wallet. You wouldn't keep your entire net worth in cash in your pocket. Don't keep all your Bitcoin on your phone. Only keep Bitcoin on your phone if you plan to spend it and are willing to lose it. Bitcoin that you self-custody in cold storage is like burying gold in the woods. If you do a good job of hiding it, it will be pretty secure. But if you lose or forget your record of where it is, there won't be anyone you can call for help. It will be lost forever. Bitcoin you store on an exchange is like money in a bank account. You still need to keep your account secure from hackers, so make sure you enable two-factor protection and don't use your phone number as your second factor. But if you forget your password, the exchange can help you recover it. You do need to trust the bank slash exchange, though, both to keep your money secure and to give it back to you when you need it. Finally, don't trust. Verify. Bitcoin is unstoppable money, which makes it extremely useful for criminals. If they can steal your Bitcoin or scam you out of it, there's nothing anyone can do to force them to give it back. That means that criminals in the cryptocurrency markets are painstakingly recreating every con in the history of money and updating them with a cryptocurrency spin. If you see an offer that sounds too good to be true, it almost certainly is. Assume that everything is a trap unless it is proven otherwise. A really common example of this is the giveaway scam. Scammers will pretend that they're a prominent figure in the community like Elon Musk or Vitalik Buterin and claim that they're celebrating something by giving away Bitcoin or Ethereum. These scams promise that you can send money to their address and they will send double that money back to you. But the second part never happens. They just take your money and disappear. Nobody wants to give you money for free. You should never share your private key with anyone and you should never send anyone money unless you want them to have it. So these are the four simple rules to keep top of mind as you first start exploring the cryptocurrency space. Make a plan and stick to it, choose your exchange carefully, store your coins carefully, and don't trust easily. I hope this introduction has been useful for you all. If you'd like to learn more, I have a free newsletter and podcast available at somethinginteresting.news. We cover cryptocurrency news and developments along with my explanations and commentary. I also answer reader submitted questions, so feel free to ask about anything that we didn't get a chance to cover here. Thanks for listening.