U Archives - BTC Lexicon

/ ˌʌnkənˈfɜrmd /

noun

After a transaction is broadcast to the Bitcoin network, it may be included in a block that is published to the network. When that happens it is said that the transaction has been mined at a depth of 1 block. With each subsequent block that is found, the number of blocks deep is increased by one. To be secure against double spending, a transaction should not be considered as confirmed until it is a certain number of blocks deep. Note that unconfirmed transactions do not expire.

"Bitcoin transactions are usually considered unconfirmed until they are six blocks deep."

Unconfirmed

After a transaction is broadcast to the Bitcoin network, it may be included in a block that is published to the network. When that happens it is said that the transaction has been mined at a depth of 1 block. With each subsequent block that is found, the number of blocks deep is increased by one. To be secure against double spending, a transaction should not be considered as confirmed until it is a certain number of blocks deep. Note that unconfirmed transactions do not expire.

Unspent Transaction Output (UTXO)

UTXO stands for Unspent Transaction (TX) Output. Every on-chain bitcoin transaction sends bitcoin to one or more addresses, from at least zero (in case of a coinbase transaction) addresses. A bitcoin wallet balance is actually the sum of the UTXOs controlled by the wallet's private keys.