Bitcoin is a decentralized digital currency and peer-to-peer payment network that allows value to be transferred without requiring a bank or central payment operator to maintain the ledger.
The idea was introduced by the pseudonymous Satoshi Nakamoto in the 2008 paper Bitcoin: A Peer-to-Peer Electronic Cash System. The Bitcoin network began operating in January 2009 and has continued running through an open network of miners, full nodes, wallet users and software contributors.
BTC is the network’s native currency. Unlike a token issued by a company or a balance maintained by a financial institution, ownership of bitcoin is represented through cryptographic keys and transactions recorded on a public blockchain.
How Bitcoin works#
Bitcoin maintains a shared ledger containing the history of confirmed transactions.
When someone sends BTC, their wallet creates a transaction identifying the bitcoin being spent and the conditions under which the new owner will be able to spend it. The transaction is digitally signed using the sender’s private keys and broadcast to the peer-to-peer network.
Transactions waiting for confirmation can be selected by miners and included in candidate blocks. Miners compete to produce a valid Proof-of-Work hash for those blocks.
Once a block is found, full nodes independently verify it against Bitcoin’s consensus rules. Nodes do not simply trust miners: they verify transactions, signatures, block structure, issuance rules and other consensus requirements before accepting a block into their copy of the blockchain.
This distinction matters. Miners propose blocks; full nodes decide whether those blocks follow Bitcoin’s rules.
Proof of Work and Bitcoin mining#
Bitcoin uses Proof of Work to determine who can propose the next block.
Miners repeatedly hash candidate block headers using Bitcoin’s double-SHA-256 process until they find a result below the network’s current difficulty target. Because the outcome of each attempt is unpredictable, miners perform enormous numbers of hash calculations while searching for a valid block.
Bitcoin targets an average interval of approximately ten minutes between blocks.
Mining difficulty adjusts every 2,016 blocks—roughly every two weeks—to compensate for changes in the amount of computational power participating in the network. If blocks have been arriving too quickly, difficulty can increase; if they have been arriving too slowly, it can decrease.
A successful miner can receive newly issued BTC through the block subsidy together with transaction fees from transactions included in the block.
Bitcoin’s 21 million supply#
Bitcoin’s monetary policy is enforced by its consensus rules rather than by a central issuer.
The original block subsidy was 50 BTC. The subsidy is cut in half every 210,000 blocks, which works out to approximately once every four years. Bitcoin Core implements this decreasing issuance schedule directly in its consensus logic.
The commonly stated maximum issuance is:
21,000,000 BTCThis fixed issuance schedule is one of Bitcoin’s most distinctive properties. New bitcoin cannot simply be created because a company, miner or developer decides that more should exist. Fully validating nodes reject blocks that violate the network’s monetary rules.
Mining will increasingly depend on transaction fees as the block subsidy continues to decline.
What determines Bitcoin transaction fees?#
Bitcoin does not have a permanently fixed or universally low transaction fee.
Users generally choose how much fee to attach to a transaction, often with help from their wallet. When demand for block space is high, transactions offering higher fee rates may be confirmed sooner.
Fees are primarily affected by the transaction’s size in blockchain data and competition for available block space—not simply by the monetary value being transferred. A transaction moving a large amount of BTC can therefore require less block space than a complicated transaction moving a much smaller amount.
This is one of the areas where the old Chainquiry article was misleading: describing Bitcoin simply as offering “low transaction fees” ignores periods when on-chain demand can make fees considerably higher.
Bitcoin is public, not anonymous#
Bitcoin is sometimes described as anonymous, but that isn’t accurate.
The blockchain is public. Transactions, addresses and balances associated with those addresses can be inspected by anyone.
Bitcoin addresses do not automatically contain a person’s real-world identity, which makes Bitcoin more accurately described as pseudonymous. Once an address becomes linked with an identifiable person or service, blockchain activity associated with it may also become easier to trace.
Wallet behavior, address reuse and interaction with exchanges or other identifiable services can therefore affect user privacy.
SegWit and Taproot#
Bitcoin’s protocol has continued to evolve without replacing the original network.
Segregated Witness (SegWit) activated in 2017. It changed how transaction signature data is represented, improving block-space efficiency and resolving transaction malleability issues that complicated some higher-layer protocols.
Taproot activated in 2021 and introduced new spending rules built around Schnorr signatures and Merkle-based scripting structures. It can improve efficiency and provide better privacy characteristics for certain complex transactions.
Bitcoin development remains open source, with Bitcoin Core serving as one widely used full-node implementation. Development continues through public code review, testing and releases rather than through a central company controlling the protocol. Bitcoin Core remained actively maintained throughout 2026.
What is the Lightning Network?#
Bitcoin’s base layer prioritizes decentralized verification and security rather than processing every possible retail payment directly on-chain.
The Lightning Network is a separate payment layer built on Bitcoin. Participants can establish payment channels and make multiple transactions without recording every individual payment directly on the blockchain.
Channels ultimately settle back to Bitcoin, allowing Lightning to support faster and typically cheaper small-value payments while the base blockchain remains the final settlement layer.
Lightning is not a replacement for the Bitcoin blockchain; it depends on it.
What Bitcoin does not provide#
Bitcoin’s design involves trade-offs that are important to understand.
Transactions are generally irreversible after confirmation. There is no central Bitcoin support department capable of recovering BTC sent to the wrong recipient.
Self-custody also places responsibility on the owner. Losing the private keys or recovery information controlling a wallet can permanently prevent access to its funds.
Bitcoin’s exchange rate can also fluctuate substantially, sometimes over short periods. Its protocol controls issuance but does not attempt to stabilize BTC’s purchasing power against dollars or other currencies.
Proof-of-Work security also requires substantial computational work and energy expenditure by miners. That cost is part of the mechanism Bitcoin uses to make rewriting blockchain history expensive.
Finally, public blockchain data means Bitcoin should not be treated as an inherently anonymous payment system.
Who controls Bitcoin?#
There is no single company that owns the Bitcoin network.
Software developers can propose and publish changes, miners choose transactions and create candidate blocks, businesses build services around the network, and users choose which software and consensus rules they accept.
A developer cannot simply force all users to accept a protocol change. Likewise, miners cannot create arbitrary amounts of BTC or spend coins without valid signatures if fully validating nodes continue enforcing the existing consensus rules.
This separation between participants is an important part of Bitcoin’s decentralized architecture. Bitcoin.org itself explicitly notes that it is not an “official” Bitcoin website because no organization owns the network.
How to research Bitcoin independently#
Bitcoin is unusually transparent compared with many cryptocurrency projects because its protocol, software and transaction history can be examined publicly.
Users can read Satoshi Nakamoto’s original whitepaper, inspect Bitcoin Core’s source code, run their own full node, review Bitcoin Improvement Proposals and independently verify transactions and blocks rather than relying solely on an exchange, wallet provider or third-party website.
For structured technical details, official resources and current network information, see the Bitcoin (BTC) profile on Chainquiry.
Chainquiry profile:
https://chainquiry.com/projects/bitcoin/
Final perspective#
Bitcoin introduced a way for participants who do not necessarily trust one another to agree on ownership and transaction history without relying on a central ledger operator.
Its design combines public-key cryptography, a peer-to-peer network, Proof of Work, independent validation and a predictable issuance schedule.
Those properties do not remove Bitcoin’s trade-offs. Fees vary, transactions are difficult to reverse, privacy requires care, self-custody introduces responsibility and BTC’s market price remains volatile.
Understanding both the mechanics and the limitations provides a much better basis for researching Bitcoin than treating it simply as either “the future of money” or a speculative investment.
