Foundations of Blockchain

Transaction input

Transaction input provides information about the funds that will be spent by referencing the spendable transaction output:

class TxIn: 
    def __init__(self, tx_out_id, tx_out_index, signature): 
        self.tx_out_id = tx_out_id 
        self.tx_out_index = tx_out_index 
        self.signature = signature 

tx_out_id and tx_out_index are used to reference the transaction output, and the signature provides proof that the spender is the legitimate owner of the fund. Unlike Bitcoin, we have not used a Script-like language to lock and unlock the transactions. Transaction validation will be performed simply by verifying the signature with the help of an elliptical curve digital signature algorithm (ECDSA).