A method of using a plurality of blockchain transactions to execute a computer-implemented task, the method comprising the steps:
- using an unlocking script (ULS1) in a blockchain transaction (Tx2) to present at least one data item to a locking script (LS1) of another transaction (Tx1) so as to provide a result on a stack;
- generating a further unlocking script (ULS2) which comprises the result provided on the stack;
- and
- presenting the further unlocking script (ULS2) to a further locking script (LS2) such that the result from the stack is provided as input to the further locking script.