Qu’est-ce que Blockchain ?
The append-only chain of blocks that records every Bitcoin transaction, where each block commits to the one before it by hash.
A block contains a batch of transactions plus the hash of the previous block. That backward reference is what makes the chain: change anything in an old block and its hash changes, which breaks every block after it.
Because valid blocks require proof of work, rewriting history means redoing that work faster than the honest network is extending the chain. The deeper a transaction is buried, the more expensive reversing it becomes. This is why "confirmations" matter and why they are counted rather than treated as binary.
A blockchain is not inherently secure or trustworthy. Its security comes from the cost of the work behind it, not from the data structure, which is just a linked list with hashes.
Termes liés
Bloc
A batch of transactions accepted into the ledger together, produced roughly every ten minutes and limited to…
Comment ça marcheProof of work
The mechanism that secures Bitcoin: miners must find a hash below a difficulty target, which is expensive to…
Comment ça marcheConfirmation
A block containing your transaction. Each subsequent block adds another, making reversal exponentially more…
Comment ça marcheHash
A fixed-length fingerprint of arbitrary data. Bitcoin uses SHA-256: the same input always gives the same…
Cette définition fait partie du glossaire Bitcoin Logical. Pour l’explication complète, commencez par Apprendre, ou consultez les chiffres en direct sur Le Signal Bitcoin.