Foundations of Blockchain

Constructing a transaction

Transactions are created by constructing valid transaction inputs and outputs. Consumable UTXOs are fetched by the find_tx_outs_for_amount method, as described in the previous section. Transaction inputs will be created for these UTXOs. The leftover amount is used to create a change transaction:

def create_transaction(receiver_address, amount, private_key,                                      unspent_tx_outs, tx_pool): 
 
    my_address = get_public_key(private_key) 
 
    my_unspent_tx_outs_a = list(filter(lambda utxo: utxo.address == my_address, unspent_tx_outs)) 
 
    my_unspent_tx_outs = filter_tx_pool_txs(my_unspent_tx_outs_a, tx_pool) 

User's unspent transactions are filtered and will be referenced in the transaction inputs:

 incl_unspent_tx_outs, left_over_amount ...