How does Bitcoin work: a technical overview

by Jeffery Konopelski

Bitcoin is a decentralized digital currency that allows for peer-to-peer transactions without the need for intermediaries such as banks or payment processors. It was first introduced in a whitepaper by an unknown person or group using the pseudonym Satoshi Nakamoto in 2008. Bitcoin’s underlying technology, called the blockchain, is a distributed ledger that maintains a record of all transactions on the network. In this technical overview, we will explore how Bitcoin works, from the basics of transactions and mining to the intricacies of the blockchain and consensus algorithm.


At its core, Bitcoin is a system for securely transferring value between individuals without relying on a centralized intermediary. Transactions are the building blocks of the Bitcoin network, and they involve sending bitcoins from one user to another. A Bitcoin transaction consists of an input, an output, and a fee.

The input of a transaction is the previous transaction output, which serves as the source of the bitcoins being transferred. The output is the destination address, where the bitcoins are being sent. The fee is the amount paid to miners to incentivize them to include the transaction in the blockchain.

To create a transaction, a user needs a private key, which is a secret number that allows them to access their bitcoins. The private key is used to sign the transaction and prove ownership of the bitcoins being transferred.


Bitcoin transactions are verified and recorded on the blockchain by a network of computers called miners. Mining is the process of adding new transactions to the blockchain and creating new bitcoins as a reward for the miner who successfully adds a new block to the chain.

Mining involves solving complex mathematical puzzles, and the first miner to solve the puzzle and add a new block to the chain is rewarded with a certain number of bitcoins. This process is known as proof-of-work, and it is designed to ensure that the blockchain is secure and immutable.

The blockchain

The blockchain is a distributed ledger that maintains a record of all Bitcoin transactions. It is a decentralized database that is maintained by a network of computers around the world. Each block in the blockchain contains a list of transactions, a timestamp, and a cryptographic hash of the previous block. This creates a chain of blocks that is secure and tamper-proof.

The blockchain is constantly growing as new transactions are added to it. Miners work to validate new transactions and add them to the blockchain by solving complex mathematical puzzles. Once a block has been added to the chain, it cannot be altered without invalidating the entire chain. This makes the blockchain an incredibly secure and reliable way to record and verify transactions.

Consensus algorithm

The Bitcoin network relies on a consensus algorithm to ensure that all nodes on the network agree on the state of the blockchain. The consensus algorithm used by Bitcoin is called proof-of-work. In proof-of-work, miners compete to solve a mathematical puzzle, and the first miner to solve the puzzle and add a new block to the blockchain is rewarded with bitcoins.

Proof-of-work is a resource-intensive process, as miners must invest a significant amount of computational power to solve the puzzles. This helps to ensure that the blockchain is secure and resistant to attack, as it would be prohibitively expensive for any one entity to control a majority of the network’s computing power.


One of the key features of Bitcoin is its decentralized nature. There is no central authority controlling the network, and every node on the network has a copy of the blockchain. This means that there is no single point of failure and the network is resilient to attacks. In addition, Bitcoin is censorship-resistant, as transactions cannot be stopped or reversed by any central authority.

Public and private keys

Bitcoin uses public-key cryptography to secure transactions. Every user on the network has a public key and a private key. The public key is used to receive bitcoins, while the private key is used to sign transactions and prove ownership of bitcoins. Users must keep their private keys secure, as anyone who has access to the private key can access the bitcoins associated with that key.

Mining rewards and halving

When Bitcoin was first introduced, miners were rewarded with 50 bitcoins for each block they added to the blockchain. However, this reward is halved approximately every four years. In 2012, the reward was reduced to 25 bitcoins, and in 2016, it was reduced to 12.5 bitcoins. This process, known as halving, is designed to limit the supply of bitcoins and ensure that there will only ever be 21 million bitcoins in circulation.


Bitcoin forks occur when a group of users decides to create a new version of the Bitcoin software with different rules. There are two types of forks: hard forks and soft forks. A hard fork occurs when the new version of the software is not compatible with the old version, and a new blockchain is created. A soft fork occurs when the new version of the software is compatible with the old version, and the blockchain is not split.

Lightning Network

The Lightning Network is a layer 2 scaling solution for Bitcoin that allows for faster and cheaper transactions. It works by creating payment channels between users that allow them to transact off-chain. This reduces the load on the Bitcoin network and allows for more transactions to be processed at a lower cost.


Bitcoin is a complex and constantly evolving technology that has the potential to transform the financial industry. While it is still a relatively new technology, it has already attracted a significant amount of attention and investment. As more people become aware of the benefits of decentralized currencies, it is likely that Bitcoin and other cryptocurrencies will continue to gain traction and become more widely adopted.

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