What is Confirmation?
A block containing your transaction. Each subsequent block adds another, making reversal exponentially more expensive.
One confirmation means included in the most recent block. Six is a common convention for large amounts, but it is a convention rather than a protocol rule.
The right number depends on what is at stake. Reversing a transaction requires out-mining the network from before it, so the appropriate depth scales with the value and the plausibility of an attacker.
Related terms
Block
A batch of transactions accepted into the ledger together, produced roughly every ten minutes and limited to…
Wie es funktioniertReorganisation (reorg)
When nodes switch to a different chain with more accumulated work, discarding one or more recently accepted…
Wie es funktioniertTransaction
A signed instruction consuming one or more UTXOs and creating new ones. Once confirmed it cannot be reversed.
Wie es funktioniertDouble-spend
Spending the same coins twice. Preventing it without a trusted third party is the problem Bitcoin was built…
This definition is part of the Bitcoin Logical glossary. For the fuller explanation, start with Lernen, or see the live numbers on Das Bitcoin-Signal.