All the frequently asked questions which you have to know before jumping into crypto trading
The Bitcoin Network is the first successful implementation of blockchain technology.
The term “blockchain technology” typically refers to the transparent, trustless, publicly accessible ledger that allows us to securely transfer the ownership of units of value using public key encryption and proof of work methods.
The technology uses decentralized consensus to maintain the network, which means it is not centrally controlled by a bank, corporation, or government. In fact, the larger the network grows and becomes increasingly decentralized, the more secure it becomes.
The potential for blockchain technology is not limited to bitcoin. As such, it has gained a lot of attention in a variety of industries including: financial services, charities and nonprofits, the arts, and e-commerce.
Our wallet is built on an HD (or hierarchical deterministic) framework, which is the industry standard for bitcoin address generation and management. Each public address your wallet generates stems from your wallet’s xPub (or Extended Public Key). Once your public address receives an incoming payment, a new address will automatically be generated and display when you click on receive.
If you use the same address each time you receive funds, it becomes easy for anyone to track your entire payment history. This method of address generation improves privacy by automatically presenting you with a new address when you’re expecting payment.
Advanced Users: Our wallet implements BIP44 to generate accounts and addresses, and the recovery mnemonic/seed (present in legacy wallets created in 2016 and prior) implements BIP39. The seed is compatible with other BIP44/BIP39 bitcoin wallets.
Every cryptocurrency transaction must be added to the blockchain, the official public ledger of all completed transactions, in order to be considered a successful and valid transfer. The work of validating transactions and adding them to the blockchain is done by miners, which are powerful computers that make up a portion of the network and confirm its transactions. Miners spend vast amounts of computing power and energy doing this for a financial reward: with every block (a collection of transactions) added to the blockchain comes a bounty called a block reward, as well as all fees sent with the transactions that were confirmed and included in the block.
For this reason, miners have a financial incentive to prioritize the validation of transactions that include a higher fee. For someone looking to send funds and get a quick confirmation, the appropriate fee to include depends on the cryptocurrency being sent and can vary greatly, depending on a number of factors, such as transaction size and network conditions.
Your Blockchain wallet will automatically calculate the appropriate fee for sending your chosen cryptocurrency. The fee for sending ether is static (you can view the fee for sending ether by clicking “Send” and selecting Ether as the currency), while the fees for sending bitcoin, bitcoin cash, and stellar are dynamic and will be calculated by your wallet after you input the amount you want to send. This article explains bitcoin transaction fees in greater detail.
Bitcoin, as well as all other major cryptocurrencies that came after it, is built upon public-key cryptography, a cryptographic system that uses pairs of keys: public keys, which are publicly known and essential for identification, and private keys, which are kept secret and are used for authentication and encryption.
Major cryptocurrencies like Bitcoin, Ethereum, and Bitcoin Cash function using three fundamental pieces of information: the address, associated with a balance and used for sending and receiving funds, and the address’ corresponding public and private keys. The generation of a bitcoin address begins with the generation of a private key. From there, its corresponding public key can be derived using a known algorithm. The address, which can then be used in transactions, is a shorter, representative form of the public key.
The private key is what grants a cryptocurrency user ownership of the funds on a given address. The Blockchain wallet automatically generates and stores private keys for you. When you send from a Blockchain wallet, the software signs the transaction with your private key (without actually disclosing it), which indicates to the entire network that you have the authority to transfer the funds on the address you’re sending from.
The security of this system comes from the one-way street that is getting from the private key to the public address. It is not possible to derive the public key from the address; likewise, it is impossible to derive the private key from the public key. In the Blockchain.com Wallet, your 12-word Secret Private Key Recovery Phrase is a seed of all the private keys of all the addresses generated within the wallet. This is what allows you to restore access to your funds even if you lose access to your original wallet. Using the recovery phrase will allow you to recover your crypto.
Bitcoin can often refer to two things. First, the Bitcoin network that keeps track of our transactions and balances, and second, the currency that we use as the unit of value when we transact. We’ll cover both here.
The Bitcoin Network
Bitcoin’s payment network (also called the bitcoin blockchain) is what makes it possible for us to transact with one another. The network uses distributed consensus to verify and confirm transactions, and consensus is reached via a large global network of high-performance computers (called miners) running the bitcoin software.
Whenever someone sends a transaction it is broadcast instantly to the network and verified by the miners. Miners are constantly working to confirm individual transactions and include them in the next block of transactions in the chain. Once a new block is verified, all the transactions within it are permanently recorded on the blockchain. Rewards are paid out in bitcoin to miners who confirm transactions and verify the next block as a way to incentivize productivity on the network.
Each party who participates in the mining process has an identical up-to-date copy of the blockchain or public ledger, which is a record of all the transactions in bitcoin history. Each party’s copy of the ledger is updated every time a new block is found.
The unit of value that we send and receive on the Bitcoin network is also referred to as bitcoin, or bitcoins. Bitcoin is completely digital, meaning we can’t physically hold it in our hand. It’s also portable, divisible, fungible, and irreversible.
Bitcoin’s existence began with an academic paper written in 2008 by a developer under the name of Satoshi Nakamoto.
The paper described the foundation for what was intended to be a peer-to-peer electronic cash system that was secure, affordable, and efficient far beyond conventional banking standards. The system Satoshi described was developed into open-source software and the first bitcoin transaction (also known as the Genesis Block) was confirmed on January 3, 2009.
Blocks are found in the Bitcoin blockchain. Blocks connect all transactions together. Transactions are combined into single blocks and are verified every ten minutes through mining. Each subsequent block strengthens the verification of the previous blocks, making it impossible to double spend bitcoin transactions (see double spend below).
Bitcoin Improvement Proposal or BIP, is a technical design document providing information to the bitcoin community, or describing a new feature for bitcoin or its processes or environment which affect the Bitcoin protocol. New features, suggestions, and design changes to the protocol should be submitted as a BIP. The BIP author is responsible for building consensus within the community and documenting dissenting opinions.
The Bitcoin blockchain is a public record of all Bitcoin transactions. You might also hear the term used as a “public ledger.” The blockchain shows every single record of bitcoin transactions in order, dating back to the very first one. The entire blockchain can be downloaded and openly reviewed by anyone, or you can use a block explorer to review the blockchain online.
The block height is just the number of blocks connected together in the block chain. Height 0 for example refers to the very first block, called the “genesis block.”
When a block is successfully mined on the bitcoin network, there is a block reward that helps incentivize miners to secure the network. The block reward is part of a “coinbase” transaction which may also include transaction fees. The block rewards halves roughly every four years; see also “halving.”
Let’s say you are spending $1.90 in your local supermarket, and you give the cashier $2.00. You will get back .10 cents in change. The same logic applies to bitcoin transactions. Bitcoin transactions are made up of inputs and outputs. When you send bitcoins, you can only send them in a whole “output.” The change is then sent back to the sender.
The term cold storage is a general term for different ways of securing your bitcoins offline (disconnected from the internet). This would be the opposite of a hot wallet or hosted wallet, which is connected to the web for day-to-day transactions. The purpose of using cold storage is to minimize the chances of your bitcoins being stolen from a malicious hacker and is commonly used for larger sums of bitcoins.
A confirmation means that the bitcoin transaction has been verified by the network, through the process known as mining. Once a transaction is confirmed, it cannot be reversed or double spent. Transactions are included in blocks.
Cryptography is used in multiple places to provide security for the Bitcoin network. Cryptography, which is essentially mathematical and computer science algorithms used to encrypt and decrypt information, is used in bitcoin addresses, hash functions, and the blockchain.
Having a decentralized bitcoin network is a critical aspect. The network is “decentralized,” meaning that it’s void of a centralized company or entity that governs the network. Bitcoin is a peer-to-peer protocol, where all users within the network work and communicate directly with each other, instead of having their funds handled by a middleman, such as a bank or credit card company.
Difficulty is directly related to Bitcoin mining (see mining below), and how hard it is to verify blocks in the Bitcoin network. Bitcoin adjusts the mining difficulty of verifying blocks every 2016 blocks. Difficulty is automatically adjusted to keep block verification times at ten minutes.
If someone tries to send a bitcoin transaction to two different recipients at the same time, this is double spending. Once a bitcoin transaction is confirmed, it makes it nearly impossible to double spend it. The more confirmations that a transaction has, the harder it is to double spend the bitcoins.
A full node is when you download the entire blockchain using a bitcoin client, and you relay, validate, and secure the data within the blockchain. The data is bitcoin transactions and blocks, which is validated across the entire network of users.
Bitcoins have a finite supply, which makes them scarce. The total amount that will ever be issued is 21 million. The number of bitcoins generated per block is decreased 50% every four years. This is called “halving.” The final halving will take place in the year 2140.
The hash rate is how the Bitcoin mining network processing power is measured. In order for miners to confirm transactions and secure the blockchain, the hardware they use must perform intensive computational operations which is output in hashes per second.
A transaction hash (sometimes referred to as a transaction ID or txid) is a unique identifier that can be used on any block explorer to look up all of the public details of a particular transaction. Every on-chain transaction has a unique hash made up of a long string of alphanumeric characters.
Bitcoin mining is the process of using computer hardware to do mathematical calculations for the Bitcoin network in order to confirm transactions. Miners collect transaction fees for the transactions they confirm and are awarded bitcoins for each block they verify.
As part of bitcoin mining, mining “pools” are a network of miners that work together to mine a block, then split the block reward among the pool miners. Mining pools are a good way for miners to combine their resources to increase the probability of mining a block, and also contribute to the overall health and decentralization of the bitcoin network.
A private key is a string of data that shows you have access to bitcoins in a specific wallet. Think of a private key like a password; private keys must never be revealed to anyone but you, as they allow you to spend the bitcoins from your bitcoin wallet through a cryptographic signature.
Proof of Work
Proof of work refers to the hash of a block header (blocks of bitcoin transactions). A block is considered valid only if its hash is lower than the current target. Each block refers to a previous block adding to previous proofs of work, which forms a chain of blocks, known as a blockchain. Once a chain is formed, it confirms all previous Bitcoin transactions and secures the network.
A public bitcoin address is cryptographic hash of a public key. A public address typically starts with the number “1.” Think of a public address like an email address. It can be published anywhere and bitcoins can be sent to it, just like an email can be sent to an email address. Learn how to receive bitcoin in your bitcoin wallet here.
RBF stands for Replace By Fee, and refers to a method that allows a sender to replace a “stuck” or unconfirmed transaction with a new one that uses a higher fee. This is done to make sure a transaction confirms as quickly as possible. The “replacement” transaction uses the same inputs as the original one. This is not considered a double spend, as the receiving address(es) typically remain the same.
Bitcoin’s existence began with an academic paper written in 2008 by a developer under the name of Satoshi Nakamoto. Satoshi is the name used as the original inventor of Bitcoin. You can learn more about Satoshi here.
A transaction is when data is sent to and from one bitcoin address to another. Just like financial transactions where you send money from one person to another, in bitcoin you do the same thing by sending data (bitcoins) to each other. Bitcoins have value because it’s based on the properties of mathematics, rather than relying on physical properties (like gold and silver) or trust in central authorities, like fiat currencies.
Just like with paper dollars you hold in your physical wallet, a bitcoin wallet is a digital wallet where you can store, send, and receive bitcoins securely. There are many varieties of wallets available, whether you’re looking for a web or mobile solution. Ideally, a bitcoin wallet will give you access to your public and private keys. This means that only you have rightful access to spend these bitcoins, whenever you choose to.
Block Explorers provide a visually appealing and intuitive way to navigate a cryptocurrency’s blockchain. Our Block Explorer launched in August 2011. It began as a way for anyone to study bitcoin transactions, along with a variety of helpful charts and statistics about activity on the network.
To look up a bitcoin transaction, users can visit https://www.blockchain.com/explorer and use the search bar on the upper right to learn more about a particular bitcoin address, transaction hash, or block number by entering it in the search field.
Once you click enter, information about your search query will display.
Take a look at this transaction we found on the blockchain as an example.
Transactions are the most important aspect of the Bitcoin network. Everything else is built and designed to ensure transactions can be effectively broadcast, validated, and confirmed. Transactions are made up of inputs and outputs; inputs are what go into a transaction (roughly speaking, inputs make up what is being sent), and outputs are what come out (making up what is being received). The outputs of one transaction can then be spent as the inputs of another one. To read a more in-depth explanation of inputs and outputs, visit our article on change addresses.
Nodes track spendable transaction outputs, or outputs that have not yet been used in another, subsequent transaction. These are known as unspent transaction outputs (UTXOs). When you view your transaction on the Blockchain.com Explorer, you will see the transaction inputs on the left and the outputs on the right. Each output will have either a red or a green icon next to it. Red means the output has already been spent in a subsequent transaction, and cannot be spent again. Green means the output is a UTXO, and is available for spending. Hover over the icon to see if an output is spent or unspent.
The only exception to the output and input chain is the coinbase transaction, which is the first transaction in every block. This transaction creates brand-new bitcoin by paying out the block reward to the miner that added the block to the blockchain. The input of this transaction is not a UTXO from a previous transaction, but rather a special type of input called the coinbase. This is also the process by which the bitcoin money supply increases until it hits the cap of 21 million bitcoin.
Although most transactions are structured as payments to addresses (based on a script called Pay-to-Public-Key-Hash, or P2PKH), bitcoin transactions can use other types of scripts as well, and include additional data besides addresses and amounts. On the Blockchain.com Explorer, these will be listed at the bottom of the transaction page under the Outputs header.
Altcoins are cryptocurrencies other than Bitcoin. They share characteristics with Bitcoin but are also different from them in other ways. For example, some altcoins use a different consensus mechanism to produce blocks or validate transactions. Or, they distinguish themselves from Bitcoin by providing new or additional capabilities, such as smart contracts or low-price volatility.
As of March 2021, there were almost 9,000 cryptocurrencies. According to CoinMarketCap, altcoins accounted for over 40% of the total cryptocurrency market in March 2021.1Because they are derived from Bitcoin, altcoin price movements tend to mimic Bitcoin’s trajectory. However, analysts say the maturity of cryptocurrency investing ecosystems and the development of new markets for these coins will make price movements for altcoins independent of Bitcoin’s trading signals.