Blockchain
A blockchain is a shared, append-only record of transactions kept by many independent computers, so no single party can rewrite it.
What Is a Blockchain?
A blockchain is a ledger made of blocks, each holding a batch of transactions and the hash of the previous block. Changing an old block would change every hash after it, so history becomes harder to alter the more blocks are built on top of it.
Thousands of nodes keep their own copy and check every block against the same rules. A consensus mechanism, such as proof of work (Bitcoin) or proof of stake (Ethereum), decides who adds the next block.
Coins never leave the blockchain: a wallet, including a hardware wallet, only holds the keys that authorise moving them. That is why losing the keys loses access, while losing the device does not lose the coins if the recovery phrase is backed up.
Ledger is a brand of hardware wallets that securely store cryptocurrency private keys offline, such as the Ledger Nano series.
Read full definitionA node is a computer running blockchain software that connects to the network, validates transactions, and maintains a copy of the ledger.
Read full definitionA consensus mechanism is a protocol that enables blockchain networks to agree on valid transactions and the ledger's state without a central authority.
Read full definitionProof of Work (PoW) is a blockchain consensus mechanism where miners solve complex cryptographic puzzles to validate transactions, add new blocks, and earn rewards.
Read full definitionBitcoin (BTC) is the first decentralized cryptocurrency, launched in 2009. It uses blockchain technology for secure, peer-to-peer digital transactions without intermediaries.
Read full definitionProof of Stake (PoS) is a blockchain consensus mechanism. Validators create new blocks based on staked cryptocurrency amounts, not computational power.
Read full definitionEthereum is a decentralized blockchain platform that enables smart contracts and decentralized applications (dApps). Its native cryptocurrency is Ether (ETH).
Read full definitionA mnemonic phrase is a set of words that stores a cryptocurrency wallet's private keys, allowing users to recover access if lost.
Read full definitionReal-World Examples
Example 1: A Bitcoin payment is broadcast, included in a block, and becomes harder to reverse with each block added after it.
Example 2: A user's hardware wallet breaks; their coins remain on the blockchain and are restored on a new device from the recovery phrase.
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 definitionA mnemonic phrase is a set of words that stores a cryptocurrency wallet's private keys, allowing users to recover access if lost.
Read full definitionReady to Choose a Secure Wallet?
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