Concurrent state machine processing using a blockchain

A system, comprising:

• a processor;
• and
• memory including executable instructions that, as a result of execution by the processor, causes the system to perform the computer-implemented method comprising:
• creating an unlocking transaction that includes:
• a transaction input comprising a hash that is a transaction ID (TxID) of a previous transaction (Tx Z) and an output (n) of the previous transaction;
• an unlocking script, the unlocking script comprising:
• a serialized version of the previous transaction (TxZ);
• a serialized version of a further previous transaction (TxZ′) with an output that was transferred by the previous transaction (TxZ);
• a set of serialized unlocking transaction fields of the unlocking transaction;
• and
• a byte that indicates which unlocking transaction fields of the unlocking transaction have been included in the unlocking script;
• and
• an output comprising a locking script of the unlocking transaction.