Cryptocurrency

• 1. Introduction

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  Cryptocurrency is a type of digital asset that exists entirely outside the traditional banking system, secured not by vaults or governments but by mathematics. In February 2014, the world's largest bitcoin exchange at the time, Mt. Gox, declared bankruptcy, claiming it had lost nearly 750,000 bitcoins belonging to its clients - roughly 7% of all bitcoins in existence, worth about $473 million. The price of a single bitcoin plunged from a high of around $1,160 in December to under $400 in February. That collapse was not the beginning of the story, nor would it be the end. What drove people to build a currency based on cryptography? How does it actually work? And why have governments from El Salvador to China taken such wildly different stances on whether it should exist at all?

• 2. Origins and Early Pioneers

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  In 1983, American cryptographer David Chaum first conceived of a type of cryptographic electronic money he called ecash. Twelve years later, in 1995, he brought that idea to life through a company called Digicash. The system required users to run special software that would withdraw digital notes from a bank and assign them specific encrypted keys before passing them along - a method that kept the currency invisible to outside parties.

  The National Security Agency took notice of these ideas. In 1996, the NSA published a paper titled "How to Make a Mint: The Cryptography of Anonymous Electronic Cash", which first appeared in an MIT mailing list in October of that year and was later published in The American Law Review in April 1997.

  Other researchers were working in parallel. In 1998, Wei Dai described "b-money", an anonymous distributed electronic cash system. Around the same time, Nick Szabo proposed "bit gold", a digital currency system in which users would generate money by completing mathematical proof-of-work functions whose solutions were cryptographically chained together and made public.

  All of these ideas fed into what came next. In January 2009, a pseudonymous developer calling himself Satoshi Nakamoto created bitcoin. It used SHA-256, a cryptographic hash function, to power its proof-of-work system. Nakamoto left behind one direct statement about the philosophy driving the project: "It's very attractive to the libertarian viewpoint if we can explain it properly," he wrote in 2008.

• 3. How the Technology Works

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  Every cryptocurrency rests on a blockchain - a continuously growing list of records called blocks, each linked to the one before it using cryptography. Each block holds a hash pointer to a previous block, a timestamp, and transaction data. Once data is recorded in a block, changing it would require altering every subsequent block, which in turn would require the agreement of the majority of the network. That structural resistance to tampering is the core security guarantee.

  The computers that maintain this network are called nodes. Each node holds a copy of the entire blockchain for the cryptocurrency it supports. When a transaction happens, the node that initiated it broadcasts the details to every other node in the network using encryption, so the transaction becomes known to everyone at once.

  Validating those transactions requires effort - specifically, what is called proof-of-work. Miners use specialized hardware to run complex hashing algorithms, racing to solve mathematical puzzles. Successful miners earn new coins as a reward, which also creates an incentive to keep the network running. The computing equipment involved has grown increasingly specialized: FPGAs and ASICs, dedicated chips built specifically for hashing, have largely replaced general-purpose computers in competitive mining. Intel marketed its own version of such a chip under the name Blockscale.

  An alternative approach, called proof-of-stake, replaces that computational race with a different mechanism: validators must prove they hold a certain amount of the currency itself. Peercoin, created in August 2012, was an early experiment that combined both proof-of-work and proof-of-stake. In September 2022, Ethereum completed a transition to pure proof-of-stake in a process called "the Merge". According to the Ethereum founder, that switch cut both energy use and carbon dioxide emissions by 99.9%.

• 4. Altcoins, Stablecoins, and Memecoins

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  In April 2011, Namecoin was created as an attempt at building a decentralized domain name system. In October 2011, Litecoin followed, using a different hash function called scrypt rather than SHA-256. Litecoin was designed to process a block every 2.5 minutes, compared to bitcoin's 10-minute interval, allowing transactions to confirm faster.

  By early 2020, there were more than 5,000 cryptocurrencies in existence. Paul Vigna of The Wall Street Journal described these alternatives to bitcoin in 2020 as "alternative versions of Bitcoin", reflecting its role as the original model. A Polytechnic University of Catalonia thesis from 2021 offered a broader definition, encompassing every cryptocurrency other than bitcoin.

  Stablecoins attempted to solve the volatility problem by pegging their value to a stable asset, typically a fiat currency. The design was not foolproof. On the 11th of May 2022, Terra's stablecoin UST fell from $1 to 26 cents. The subsequent collapse of Terraform Labs resulted in the loss of nearly $40 billion invested across the Terra and Luna coins. In September 2022, South Korean prosecutors sought an Interpol Red Notice against the company's founder, Do Kwon.

  At the other end of the seriousness spectrum sit memecoins: cryptocurrencies born from internet jokes. Dogecoin, built around the Shiba Inu dog from the Doge meme, hit a record high of 73 cents before falling to 13 cents by mid-2024. Scams cluster around the memecoin category, and the record-breaking volatility of even the best-known examples makes the broader cryptocurrency market look stable by comparison.

• 5. Volatility and Market Crashes

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  Cryptocurrency has passed through several sharp cycles of growth and collapse: notable crashes occurred in 2011, during 2013-2014/15, during 2017-2018, and during 2021-2023. Over one week in May 2022, bitcoin lost 20% of its value and Ethereum lost 26%, while Solana and Cardano fell 41% and 35% respectively. During that same week, the Nasdaq fell 7.6% and the FTSE 100 fell 3.6%, placing cryptocurrency losses on a different scale entirely.

  Of the ten leading cryptocurrencies by total market value in January 2018, only four - bitcoin, Ethereum, Cardano, and Ripple (XRP) - were still in that top group in early 2022. The total value of all cryptocurrencies reached $2 trillion at the end of 2021 but had halved within nine months.

  The FTX collapse illustrated how institutional fragility compounded individual loss. On the 11th of November 2022, FTX Trading Ltd., a cryptocurrency exchange that had also operated a crypto hedge fund and had been valued at $18 billion, filed for bankruptcy. On the 2nd of November 2023, Sam Bankman-Fried was found guilty on seven counts of fraud related to FTX. On the 28th of March 2024, the court sentenced him to 25 years in prison.

  A Pew Research Center survey from October 2024 found that 63% of adults in the US had little to no confidence that current ways to invest in, trade, or use cryptocurrencies were reliable and safe. The same survey found that 17% of US adults had directly interacted with cryptocurrency - a figure statistically unchanged from 2021.

• 6. Energy, Environment, and Mining Geography

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  Mining for proof-of-work cryptocurrencies demands enormous quantities of electricity. Proof-of-work blockchains including bitcoin, Ethereum, Litecoin, and Monero were estimated to have added between 3 million and 15 million tons of carbon dioxide to the atmosphere between the 1st of January 2016 and the 30th of June 2017. By November 2018, bitcoin alone was estimated to consume 45.8 terawatt-hours annually, generating between 22.0 and 22.9 million tons of CO2 - rival to Jordan and Sri Lanka. By the end of 2021, that figure had grown to an estimated 65.4 million tons, comparable to the emissions of Greece. A 2023 IMF working paper projected that crypto mining could generate 450 million tons of emissions by 2027, accounting for 0.7% of global emissions.

  Bitcoin uses 707.6 kilowatt-hours of electricity per transaction. By comparison, XRP, the world's most energy-efficient cryptocurrency, uses just 0.0079 kilowatt-hours per transaction. A study of six major proof-of-stake networks in May 2021 found that Polkadot consumed the least electricity overall, using the equivalent of seven average US homes per year. The research concluded that proof-of-stake networks collectively consumed 0.001% of the electricity the bitcoin network does.

  Geography has shaped where mining happens, driven by the price of electricity and climate. Before June 2021, China was the primary location for bitcoin mining. After China drove out those operations, the United States became the top global leader. A mining facility in Dalton, Georgia now consumes roughly the same electricity as 97,000 nearby households. Riot Platforms operates a facility in Rockdale, Texas that consumes approximately as much electricity as 300,000 nearby households, making it the most energy-intensive bitcoin mining operation in the country. In 2021, Kazakhstan became the second-largest cryptocurrency mining country, producing 18.1% of the global exahash rate, and built a compound near Ekibastuz containing 50,000 computers.

• 7. Regulation, Crime, and Legal Status

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  According to the Library of Congress in 2021, an absolute ban on trading or using cryptocurrencies applied in nine countries: Algeria, Bangladesh, Bolivia, China, Egypt, Iraq, Morocco, Nepal, and the United Arab Emirates. An implicit ban applied in another 39 countries or regions.

  On the 9th of June 2021, El Salvador announced it would adopt bitcoin as legal tender, becoming the first country to do so after its Legislative Assembly voted 62-22 to pass a bill submitted by President Nayib Bukele. In September 2021, the Chinese government completed its crackdown by declaring all cryptocurrency transactions of any kind illegal. In November 2024, the UK's incoming Labour government confirmed plans to proceed with regulation, with new requirements expected to come into force in 2026.

  Crime has tracked the money throughout. Blockchain data company Chainalysis found that criminals laundered $8.6 billion worth of cryptocurrency in 2021, up 30% from the prior year. Almost 74% of ransomware revenue in 2021 - over $400 million - went to software strains likely affiliated with Russia. Between 2011 and 2019, reported breaches at exchanges and storage providers ranged from four to twelve per year.

  Concentration of holdings compounds the structural risk. A 2021 paper from the National Bureau of Economic Research found that the top 10,000 bitcoin addresses controlled about one-third of all bitcoin in circulation. Among miners specifically, 0.01% controlled 50% of the capacity. Researcher Flipside Crypto found that less than 2% of anonymous accounts controlled 95% of all available bitcoin supply. In February 2023, the SEC ruled that crypto exchange Kraken's staking program operated as an illegal securities seller; Kraken agreed to a $30 million settlement and ceased its US staking service.