This invention relates generally to distributed ledger technology (including blockchain related technologies), and in particular the use of a blockchain in implementing, controlling and/or automating a task or process. It may relate to the use of a blockchain or related technology for recording or representing the execution of a portion of logic. This portion of logic may be arranged to implement the functionality of a logic gate, or plurality of logic gates, such as AND, XOR, NOT, OR etc. . . . . An embodiment of the invention may comprise the steps of: providing a blockchain Transaction comprising a redeem script for an output, wherein the redeem script comprises: i) a plurality of public keys, each associated with a corresponding private key; and wherein each public key is uniquely associated with a potential state of at least one data source; and wherein a minimum number of said private keys must be used to sign an unlocking script of a further blockchain Transaction in order to spend the output; and ii) logic arranged to provide a result based on: A) a determination of which of the plurality of associated private key(s) is/are used to sign the unlocking script, so as to provide an interim result: and B) a comparison of a parameter supplied via the unlocking script against the interim result. The method also comprises the step of attempting to spend the transaction output more than once, each attempt supplying a different parameter.