Foundations of Blockchain

UTXO

A transaction input will always refer to a UTXO. A list of UTXOs is maintained locally. This list is updated whenever a transaction is processed, and is referred to during transaction validation. Although this list could be generated at any time by traversing the entire blockchain, it is maintained in memory to facilitate speedy transaction validation:

class UnspentTxOut: 
    def __init__(self, tx_out_id, tx_out_index, address, amount): 
        self.tx_out_id = tx_out_id 
        self.tx_out_index = tx_out_index 
        self.address = address 
        self.amount = amount 

The list of UTXOs is a simple list that is initially created by processing the genesis transaction.

self.unspent_tx_outs = process_transactions([self.genesis_transaction], [], 0)

Whenever the node creates ...