Bitcoin Core
Bitcoin Core is the reference software of the Bitcoin network: a full node that verifies every block and transaction, with a built-in wallet.
What Is Bitcoin Core?
Bitcoin Core is the reference software of the Bitcoin network. It descends directly from the program Satoshi Nakamoto released, is maintained as an open-source project by a large group of contributors, and is the software most of the network's full nodes run.
Running it turns a computer into a full node: it downloads the blockchain, checks every block and transaction against the consensus rules, and relays valid ones to other nodes. The owner then learns the state of their coins from their own copy instead of asking a third party's server, which helps both verification and privacy.
Bitcoin Core also contains a wallet. Used alone, it keeps private keys on the computer, which makes it a hot wallet. With a hardware wallet, it can hold only the public keys and pass transactions to the device for signing through its external signer feature and the HWI tool. Many people instead connect a coordinator such as Sparrow or Specter to their node and use the hardware wallet there.
The costs are disk space, bandwidth and an initial synchronisation that can take from hours to days depending on the hardware. Pruned mode reduces storage by discarding old block data after it has been verified.
Bitcoin (BTC) is the first decentralized cryptocurrency, launched in 2009. It uses blockchain technology for secure, peer-to-peer digital transactions without intermediaries.
Read full definition: BitcoinA Satoshi is the smallest unit of Bitcoin, equal to 0.00000001 BTC. It is named after Bitcoin's creator, Satoshi Nakamoto.
Read full definition: SatoshiA Full Node is a computer that stores the entire blockchain and verifies all transactions, ensuring network security and consistency in cryptocurrency systems like Bitcoin.
Read full definition: Full NodeA node is a computer running blockchain software that connects to the network, validates transactions, and maintains a copy of the ledger.
Read full definition: NodeA blockchain is a shared, append-only record of transactions kept by many independent computers, so no single party can rewrite it.
Read full definition: BlockchainA private key is the secret number that proves ownership of a crypto address and signs its transactions. Whoever has it controls the funds.
A Hot Wallet is a cryptocurrency wallet connected to the internet, allowing for easy access and transactions but more vulnerable to hacks.
Read full definition: Hot WalletA hardware wallet is a dedicated device that keeps private keys offline and signs transactions internally, so the keys never reach an internet-connected computer or phone.
A public key is computed from a private key and lets anyone verify its signatures. Addresses are derived from public keys; knowing one does not allow spending.
Read full definition: Public KeyAn external signer is a hardware wallet or remote device that signs cryptocurrency transactions securely, keeping private keys isolated from the connected software wallet.
Read full definition: External SignerSparrow Wallet is a desktop Bitcoin wallet that focuses on security, privacy, and advanced features for managing Bitcoin transactions and keys.
Read full definition: Sparrow WalletSpecter is a pair of open-source Bitcoin projects: Specter Desktop, a multisig coordinator app for hardware wallets, and Specter DIY, a signing device that users build themselves.
Read full definition: SpecterReal-World Examples
Example 1: A user points Sparrow at their own Bitcoin Core node and signs with a Coinkite Coldcard Mk5. Address and balance lookups go to their own node and not to a public server.
Example 2: Someone expecting a large payment to their hardware wallet waits until their own node shows the confirmations, without relying on a block explorer website.
Sparrow Wallet is a desktop Bitcoin wallet that focuses on security, privacy, and advanced features for managing Bitcoin transactions and keys.
Read full definition: Sparrow WalletBitcoin (BTC) is the first decentralized cryptocurrency, launched in 2009. It uses blockchain technology for secure, peer-to-peer digital transactions without intermediaries.
Read full definition: BitcoinA node is a computer running blockchain software that connects to the network, validates transactions, and maintains a copy of the ledger.
Read full definition: NodeA hardware wallet is a dedicated device that keeps private keys offline and signs transactions internally, so the keys never reach an internet-connected computer or phone.
A block explorer is a website that shows the public contents of a blockchain: transactions, addresses, balances and blocks.
Read full definition: Block ExplorerFrequently Asked Questions
Can I use Bitcoin Core with a hardware wallet?
Yes. Bitcoin Core can hold only the public keys and pass transactions to the device for signing through its external signer feature and the HWI tool. Many people instead connect a coordinator such as Sparrow or Specter to their own node and use the hardware wallet there, so lookups still go to their own copy of the blockchain.
Is the Bitcoin Core wallet a hot wallet?
Used on its own, yes: it keeps the private keys on the computer, which is connected to the internet. Paired with a hardware wallet it is different, because Bitcoin Core then holds only public keys and the device does the signing. The full node part of the software verifies blocks and transactions either way.
How much storage and time does running Bitcoin Core need?
It needs disk space for the blockchain, bandwidth, and an initial synchronisation that can take from hours to days depending on the hardware. Pruned mode reduces storage by discarding old block data after it has been verified, so the node still checks every block without keeping the full history on disk.
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