Bitcoin (BTC) is a cryptocurrency, a virtual currency designed to act as money and a form of payment outside the control of any one person, group, or entity, thus removing the need for third-party involvement in financial transactions. It is rewarded to blockchain miners for the work done to verify transactions and can be purchased on several exchanges.
Bitcoin was introduced to the public in 2009 by an anonymous developer or group of developers using the name Satoshi Nakamoto.
It has since become the most well-known cryptocurrency in the world. Its popularity has inspired the development of many other cryptocurrencies. These competitors either attempt to replace it as a payment system or are used as utility or security tokens in other blockchains and emerging financial technologies.
Learn more about the cryptocurrency that started it all—the history behind it, how it works, how to get it, and what it can be used for.
• Launched in 2009, Bitcoin is the world's largest cryptocurrency by market capitalization.
• Unlike fiat currency, Bitcoin is created, distributed, traded, and stored using a decentralized ledger system known as a blockchain.
• Bitcoin and its ledger are secured by proof-of-work (PoW) consensus, which is also the "mining" process that introduces new bitcoins into the system.
• Bitcoin can be purchased via various cryptocurrency exchanges.• Bitcoin's history as a store of value has been turbulent; it has gone through several boom and bust cycles over its relatively short lifespan.
• As the first decentralized virtual currency to meet widespread popularity and success, Bitcoin has inspired a host of other cryptocurrencies in its wake.
In August 2008, the domain name Bitcoin.org was registered. Today, at least, this domain is WhoisGuard Protected, meaning the identity of the person who registered it is not public information.
In October 2008, a person or group using the false name Satoshi Nakamoto announced the Cryptography Mailing List at metzdowd.com: "I've been working on a new electronic cash system that's fully peer-to-peer, with no trusted third party." This now-famous white paper published on Bitcoin.org, entitled "Bitcoin: A Peer-to-Peer Electronic Cash System," would become the Magna Carta for how Bitcoin operates today.
On Jan. 3, 2009, the first Bitcoin block was mined—Block 0. This is also known as the "genesis block" and contains the text: "The Times 03/Jan/2009 Chancellor on brink of second bailout for banks," perhaps proof that the block was mined on or after that date, and maybe also as relevant political commentary.
Bitcoin rewards are halved every 210,000 blocks. For example, the block reward was 50 new bitcoins in 2009. On May 11, 2020, the third halving occurred, bringing the reward for each block discovery down to 6.25 bitcoins.
One bitcoin is divisible to eight decimal places (100 millionths of one bitcoin), and this smallest unit is referred to as a satoshi. If necessary, and if the participating miners accept the change, Bitcoin could eventually be made divisible to even more decimal places.
Bitcoin, as a form of digital currency, isn't too complicated to understand. For example, if you own a bitcoin, you can use your cryptocurrency wallet to send smaller portions of that bitcoin as payment for goods or services. However, it becomes very complex when you try to understand how it works.
Bitcoin isn't too complicated to understand as a form of digital currency. For example, if you own a bitcoin, you can use your cryptocurrency wallet to send smaller portions of that bitcoin as payment for goods or services. However, it becomes very complex when you try to understand how it works.
Cryptocurrencies are part of a blockchain and the network required to power it. A blockchain is a distributed ledger, a shared database that stores data. Data within the blockchain is secured by encryption methods.
When a transaction takes place on the blockchain, information from the previous block is copied to a new block with the new data, encrypted, and the transaction is verified by validators—called miners—in the network. When a transaction is verified, a new block is opened, and a Bitcoin is created and given as a reward to the miner(s) who verified the data within the block—they are then free to use it, hold it, or sell it.
Transactions are placed into a queue to be validated by miners within the network. Miners in the Bitcoin blockchain network all attempt to verify the same transaction simultaneously. The mining software and hardware work to solve for the nonce, a four-byte number included in the block header.
The block header is hashed, or randomly regenerated by a miner repeatedly until it meets a target number specified by the blockchain. The block header is "solved," and a new block is created for more transactions to be encrypted and verified.
Bitcoin uses the SHA-256 hashing algorithm to encrypt the data stored in the blocks on the blockchain. Simply put, transaction data stored in a block is encrypted into a 256-bit hexadecimal number. That number contains all the transaction data and information linked to the blocks before that block.
A variety of hardware and software can be used to mine Bitcoin. When Bitcoin was first released, it was possible to mine it competitively on a personal computer; however, as it became more popular, more miners joined the network, which lowered the chances of being the one to solve the hash. You can still use your personal computer as a miner if it has newer hardware, but the chances of solving a hash individually are minuscule.
This is because you're competing with a network of miners that generate around 444 quintillion hashes (444 exa hashes), or random number generations, per second. Machines—called Application Specific Integrated Circuits (ASICs), have been built specifically for mining—can generate up to 335 trillion hashes per second. In contrast, a computer with the latest hardware hashes around 100 megahashes per second (100 million).6
To successfully become a Bitcoin miner, you have several options. You can use your existing computer to use mining software compatible with Bitcoin and join a mining pool. Mining pools are groups of miners that combine their computational power to compete with large ASIC mining farms.
If you have the financial means, you could also purchase an ASIC miner. You can generally find a new one for around $10,000, but used ones are also sold by miners as they upgrade their systems. There are some significant costs, such as electricity and cooling, to consider if you purchase one or more ASICs.
There are several mining programs to choose from and many pools you can join. Two of the most well-known programs are CGMiner and BFGMiner. When choosing a pool, it's important to make sure you find out how they pay out rewards, what any fees might be, and read some mining pool reviews.
Speculative investors have been drawn to Bitcoin after its rapid price appreciation in recent years. Bitcoin had a price of $7,167.52 on Dec. 31, 2019, and a year later, it had appreciated more than 300% to $28,984.98. It continued to surge in the first half of 2021, trading at a record high of $68,990 in November 2021—it then fell over the next few months to hover around $40,000. As mentioned above, its price continues to fluctuate wildly.8
Thus, many people purchase Bitcoin for its investment value rather than its ability to act as a medium of exchange. However, the lack of guaranteed value and its digital nature means its purchase and use carry several inherent risks. For example, many investor alerts have been issued by the Securities and Exchange Commission (SEC), the Financial Industry Regulatory Authority (FINRA), and the Consumer Financial Protection Bureau (CFPB) regarding Bitcoin investing.
Like any new technology, the attempts at regulating Bitcoin have been difficult. The current administration seeks to impose regulations around Bitcoin but, at the same time, walks a tightrope in trying not to throttle a growing and economically beneficial industry.11
Biden has stated he will seek to prevent the illegal use of Bitcoin but also support its development. The U.S. has particularly been focused on regulating crypto and its criminal usage overseas, such as sanctioning cryptocurrency exchanges and individual cryptocurrency wallets and recovering crypto payments made to criminals.11
Bitcoin was the first cryptocurrency and is intended to be used as a form of payment outside of legal tender. Since its introduction in 2009, Bitcoin's popularity has surged and its uses expanded, resulting in the creation of many new competitor cryptocurrencies.
Though the process of generating Bitcoin is complex, investing in it is more straightforward. Investors and speculators can buy and sell Bitcoin on crypto exchanges. As with any investment, particularly one as new and volatile as Bitcoin, investors should carefully consider if Bitcoin is the right investment for them.
The comments, opinions, and analyses expressed on Investopedia are for informational purposes only. Read our warranty and liability disclaimer for more info. As of the date this article was written, the author does not own cryptocurrency.
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