METHOD AND SYSTEM FOR CONTROLLING THE PERFORMANCE OF A CONTRACT USING A DISTRIBUTED HASH TABLE AND A PEER-TO-PEER DISTRIBUTED LEDGER

1 . (canceled)

2 . A computer-implemented method for controlling the performance of a contract, the method comprising:

storing a contract on or in a computer-based repository, the contract being associated with a licence between a first user (U1) and a second user (U2), wherein the contract defines a condition which may be evaluated to true or false;

receiving over a communications network, a transaction comprising a transfer of a token from an agent (A) to the first user (U1) or the second user (U2), the transaction comprising metadata that includes an identifier indicative of a location where the contract is stored;

querying a peer-to-peer distributed ledger to determine whether the transaction comprises at least one unspent output (UTXO); and

responsive to querying the peer-to-peer distributed ledger, determining whether to modify performance of the contract.

3 . The method of claim 2 , wherein the transaction further comprises a deterministic redeem script address.

4 . The method of claim 2 , wherein the contract is a smart contract.

5 . The method of claim 2 , wherein the step of determining comprises:

terminating the contract in the event that the at least one unspent output (UTXO) cannot be identified from the peer-to-peer distributed ledger; or

maintaining the contract in the event that the at least one unspent output (UTXO) is identified from the peer-to-peer distributed ledger.

6 . The method according to claim 5 , wherein the step of terminating the contract comprises broadcasting a further transaction to spend the at least one unspent output (UTXO).

7 . The method according to either claim 6 , wherein the further transaction comprises:

an input which is the at least one unspent output (UTXO); and

a redeem script comprising a signature, the metadata, an agent public key (PA) associated with the agent, and a first user public key (PU1) associated with the first user (U1).

8 . The method according to claim 2 , wherein the contract defines:

at least one condition, the at least one condition relating to operation of the licence as between the first user (U1) and the second user (U2); and

at least one action whose performance is dependent upon the evaluation of the condition.

9 . The method according to claim 2 , wherein the step of querying the peer-to-peer distributed ledger further comprises:

checking whether the contract has been terminated by determining whether the at least one unspent output (UTXO) is present in a list of unspent transaction outputs for the peer-to-peer distributed ledger.

10 . The method according to claim 2 , wherein the contract is stored in a Distributed Hash Table (DHT).

11 . The method according to claim 2 , wherein the contract comprises a Deterministic Finite Automation (DFA) to implement the contract.

12 . The method according to claim 11 , wherein the Deterministic Finite Automation (DFA) is defined using a codification scheme.

13 . The method of claim 11 , wherein the Deterministic Finite Automation is implemented as at least one of:

i) a blockchain transaction or sequence of transactions;

ii) an agent based process or sequence of processes;

iii) a set of instructions for a smart wallet.

14 . The method according to claim 2 , further comprising the step of renewing the contract by performing the steps of:

generating a sub-key relating to a previous key associated with the contract;

generating a further redeem script comprising the sub-key, the location of the contract, and a hash of the contract; and

paying a quantity of a cryptocurrency (C) to the further redeem script.

15 . The method according to claim 2 , further comprising the step of generating a sub-contract derived from the contract, wherein the sub-contract is associated with a deterministic address and is generated by performing the steps of:

using a new public key derived using a seed;

storing the sub-contract in or on the computer-based repository with a reference to the contract;

broadcasting a sub-contract transaction to the peer-to-peer distributed ledger, the sub-contract transaction including the reference to the contract; and

adding, to the metadata associated with the contract, a reference to the sub-contract.

16 . The method of claim 2 , wherein the licence between the first user (U1) and the second user (U2) relates to one or more of:

computer software; and

digital media, including music, videos, and electronic books.

17 . The method of claim 2 , wherein the peer-to-peer distributed ledger is the blockchain.

18 . The method of claim 2 , wherein the cryptocurrency is bitcoin.

19 . A computer software program comprising machine-readable instructions to cause a processing device to implement the method of claim 2 .

20 . A computer system for controlling the performance of a contract, the system comprising a processing device configured to:

store a contract on or in a computer-based repository, the contract being associated with a licence between a first user (U1) and a second user (U2), wherein the contract defines a condition which may be evaluated to true or false;

receive, over a communications network, a transaction comprising a transfer of a token from an agent (A) to the first user (U1) or the second user (U2), the transaction comprising metadata that includes an identifier indicative of a location where the contract is stored;

query a peer-to-peer distributed ledger to determine whether the transaction comprises at least one unspent output (UTXO); and

responsive to querying the peer-to-peer distributed ledger, determine whether to modify performance of the contract.