Abstract: The invention provides systems and methods for converting high level source code into an arithmetic circuit which represents the functionality expressed in the source code. The invention comprises a translation/interpretation component for performing this conversion. In a preferred embodiment, the source code is a smart contract such as those used in relation to a blockchain platform. The invention could be used in relation to the Bitcoin network, for example. A method in accordance with an embodiment comprises the steps of: processing a portion of high level source code (e.g. a smart contract) to generate an arithmetic circuit. The arithmetic circuit comprises one or more arithmetic gates arranged to represent at least some of the functionality expressed in the source code. The processing involves evaluating one or more constants provided in the source code to produce one or more expressions that include Boolean and/or arithmetic operators.

Abstract: Systems and methods described herein relate to techniques in which multiple parties each generate and exchange quantities that are based on a shared secret (e.g., powers of the shared secret) without exposing the shared secret. According to a protocol, two or more parties may exchange sets of elliptic curve points generated over polynomials that can be used, by each of the two or more parties, to determine a power of a shared secret. The protocol may be utilized as part of determining parameters for a smart contract that is broadcast to a blockchain network (e.g., Bitcoin). Based on the protocol, an additional party (e.g., a third party different from the two or more parties) may perform a computational task such as execution of the smart contract.

Abstract: A method is provided comprising generating a blockchain transaction (Tx) indicative of a condition on use of the resource, the blockchain transaction comprising a multi-signature script requiring a plurality of signatures for completion of the blockchain transaction; providing a first subset of the plurality of signatures to the blockchain transaction to generate a partially signed signature script to partially complete the blockchain transaction; and responsive to the condition on the use of the resource being satisfied, providing a second subset of the plurality of signatures to the blockchain transaction to fully complete the blockchain transaction. The condition on the use of the resource may be the use of a discrete amount of the resource and the second subset of the plurality of signatures is provided responsive to the discrete amount of the resource being used.

Abstract: Systems and methods described herein relate to techniques in which multiple parties each generate and exchange quantities that are based on a shared secret (e.g., powers of the shared secret) without exposing the shared secret. According to a protocol, two or more parties may exchange sets of elliptic curve points generated over polynomials that can be used, by each of the two or more parties, to determine a power of a shared secret. The protocol may be utilised as part of determining parameters for a smart contract that is broadcast to a blockchain network (e.g., Bitcoin). Based on the protocol, an additional party (e.g., a third party different from the two or more parties) may perform a computational task such as execution of the smart contract.

Abstract: A computer-implemented method to validate a block at a node within a network of nodes implementing a blockchain conforming to a blockchain protocol. This may be the Bitcoin protocol or an alternative. The method includes determining, serially, that each unspent transaction output referenced as an input in each of the plurality of transactions is unique and, based on that determination allocating each transaction in the plurality of transactions to one of two or more parallel processors, and verifying, in parallel, by the two or more parallel processors, that the transactions in the plurality of transactions comply with transaction-level validation criteria. The node also determines that the block meets block-level validation criteria. If the transactions comply with transaction-level validation criteria and the block complies with block-level validation criteria, the block is deemed valid and the node forwards the block to one or more peer nodes in the network.

Abstract: Systems and methods described herein relate to techniques in which multiple parties each generate and exchange quantities that are based on a shared secret (e.g., powers of the shared secret) without exposing the shared secret. According to a protocol, two or more parties may exchange sets of elliptic curve points generated over polynomials that can be used, by each of the two or more parties, to determine a power of a shared secret. The protocol may be utilised as part of determining parameters for a smart contract that is broadcast to a blockchain network (e.g., Bitcoin). Based on the protocol, an additional party (e.g., a third party different from the two or more parties) may perform a computational task such as execution of the smart contract.

Abstract: Techniques are presented for a blockchain-implemented method and system of controlling use of or access to a parking space. The method comprises generating a blockchain transaction indicative of a condition on use of, or access to, the parking space, the blockchain transaction comprising a multi-signature script requiring a plurality of signatures for completion of the blockchain transaction; providing a first subset of the plurality of signatures to the blockchain transaction to generate a partially signed signature script to partially complete the blockchain transaction; and responsive to the condition on use of or access to the parking space being satisfied, providing a second subset of the plurality of signatures to the blockchain transaction to fully complete the blockchain transaction.

Abstract: A protocol is described which: (i) allows storage nodes to be rewarded for maintaining a public blockchain; and (ii) verifies the integrity of the blockchain with the help of a Proof-of-Blockchain Storage (PoBS) scheme. The protocol provides a way to cryptographically check if a data file stored on a remote server is intact using a challenge-response method. The protocol is secured against a man-in-the-middle attack. A malicious peer cannot pass the challenge to a third party which is storing the data and give back the response. The scheme is also publicly verifiable.

Abstract: The invention relates to distributed ledger technologies such as consensus-based blockchains. A blockchain transaction may include digital resources that are encumbered by a locking script that encodes a set of conditions that must be fulfilled before the encumbered resources may be used (e.g., transferring ownership/control of encumbered resources). A worker (e.g., a computer system) performs one or more computations to generate a proof, which is encoded as part of an unlocking script. A verification algorithm may utilize the proof, a verification key, and additional data such as a cryptographic material associated with the worker (e.g., a digital signature) to verify that digital assets of the transaction should be transferred. As a result of the validation of this transaction, any third party is able to check the contract was executed corrected rather than re-executing the contract, thus saving computational power.

Abstract: Techniques described herein may be utilized to serialise and de-serialise arithmetic circuits that are utilized in the execution of computer programs. The arithmetic circuit may be utilized to build a Quadratic Arithmetic Problem (QAP) that is compiled into a set of cryptographic routines for a client and a prover. The client and prover may utilize a protocol to delegate execution of a program to the prover in a manner that allows the client to efficiently verify the prover correctly executed the program. The arithmetic circuit may comprise a set of symbols (e.g., arithmetic gates and values) that is compressed to produce a serialised circuit comprising a set of codes, wherein the set of symbols is derivable from the set of codes in a lossless manner. Serialisation and de-serialisation techniques may be utilized by nodes of a blockchain network.

Abstract: A computer implemented method and system is described which uses blockchain technology as a storage system for data acquired from a digital twin. The blockchain can be used to generate an immutable transaction history of data produced by the digital twin. In the case of an error, failure, incident, or accident, parties of interest can then access and analyse an immutable set of data. The blockchain network can also execute a digital smart contract based on the data received from a digital twin. The invention may be used in conjunction with the Bitcoin blockchain or another blockchain protocol.

Abstract: Systems and methods described herein relate to techniques that allow for multiple parties to jointly generate or jointly agree upon the parameters for generation of a smart contract, such as a verification key. Execution of the smart contract may be performed by a third party, for example, a worker node on a blockchain network. Techniques described herein may be utilised as part of a protocol in which parties of a smart contract share powers of a secret in a manner that allows each party to determine an identical common reference string, agree on parameters for a smart contract, agree and/or make proportionate contributions the smart contract, and combinations thereof. The smart contract may be published to a blockchain network (e.g., Bitcoin Cash). The protocol may be a zero-knowledge protocol.

Abstract: In a distributed system, a first computer system may require computationally verifiable assurances of the authenticity and integrity of computations (e.g., performed as part of the execution of a program) performed by a second computer system. Methods described herein may be utilized to enforce and/or ensure the correct execution of a program. The first computer system may delegate execution of a program to a second computer system and a protocol may be employed to constrain the second computer system to perform a correct execution of the program. The protocol may include mitigation and correction routines that mitigate and/or correct the incorrect execution of a program. In various systems and methods described herein, the protocol may utilize a blockchain network such as a Bitcoin-based blockchain network.

Abstract: The invention relates to distributed ledger technologies such as consensus-based blockchains. A blockchain transaction may include digital resources that are encumbered by a locking script that encodes a set of conditions that must be fulfilled before the encumbered resources may be used (e.g., transferring ownership/control of encumbered resources). A worker (e.g., a computer system) performs one or more computations to generate a proof, which is encoded as part of an unlocking script. A verification algorithm may utilize the proof, a verification key, and additional data such as a cryptographic material associated with the worker (e.g., a digital signature) to verify that digital assets of the transaction should be transferred. As a result of the validation of this transaction, any third party is able to check the contract was executed corrected rather than re-executing the contract, thus saving computational power.

Abstract: A computer implemented method and system is described which uses blockchain technology as a storage system for data acquired from a digital twin. The blockchain can be used to generate an immutable transaction history of data produced by the digital twin. In the case of an error, failure, incident, or accident, parties of interest can then access and analyse an immutable set of data. The blockchain network can also execute a digital smart contract based on the data received from a digital twin. The invention may be used in conjunction with the Bitcoin blockchain or another blockchain protocol.

Abstract: A computer-implemented method implemented in a blockchain network is described. Validation nodes receive data regarding a newly mined block comprising a plurality of transactions and send a delete request to a distributed memory pool to delete the plurality of transactions from the distributed memory pool. Nodes storing the distributed memory pool store a plurality of transactions, the plurality of transactions forming at least part of a distributed memory pool of transactions waiting to be mined into a block of a blockchain. The computer-implemented method further comprises receiving a delete request from a validation node of the blockchain network, the delete request identifying one or more transactions which have been included in a newly mined block, the delete request indicating that the one or more transactions should be deleted from the distributed memory pool.

Abstract: The invention provides a blockchain-implemented control method and corresponding system(s). The invention may control access to an internet-enabled resource such as an IoT device that is provided with computing capabilities enabling it to communicate with other computer-based resources and interact with a distributed ledger such as a blockchain. In one embodiment, the invention provides a method for controlling the use of an internet-enabled resource comprising providing a first blockchain transaction comprising at least one output which is redeemable only by provision of at least: i) a secret value selected by a user; and ii) a signature associated with a resource provider; sending use-related information to the resource; generating a second blockchain transaction requesting at least the secret value; and modifying the second blockchain transaction to include the secret value.

Abstract: Techniques described herein may be utilized to serialise and de-serialise arithmetic circuits that are utilized in the execution of computer programs. The arithmetic circuit may be utilized to build a Quadratic Arithmetic Problem (QAP) that is compiled into a set of cryptographic routines for a client and a prover. The client and prover may utilize a protocol to delegate execution of a program to the prover in a manner that allows the client to efficiently verify the prover correctly executed the program. The arithmetic circuit may comprise a set of symbols (e.g., arithmetic gates and values) that is compressed to produce a serialised circuit comprising a set of codes, wherein the set of symbols is derivable from the set of codes in a lossless manner. Serialisation and de-serialisation techniques may be utilized by nodes of a blockchain network.

Abstract: The computer-implemented invention provides a method and corresponding system for controlling access to and/or use of an internet-enabled resource. The invention uses an electronic ledger such as, for example, the Bitcoin blockchain. The resource may be an IoT device or system. Access to the resource is permitted or enabled upon provision of a cryptographic key e.g., a private key which corresponds to a public key which has been stored in memory. In one embodiment, the public key is stored in a DHT. Access to the resource is prevented or disabled by removing the public key from memory and using a redeem script of a second blockchain Transaction to spend a tokenised output of a first blockchain Transaction. The second transaction detokenizes the token (or ‘coloured coin’) contained within the first Transaction. In order to prevent further access to the resource, an encrypted message is sent to the internet-enabled resource, wherein the message communicates a public key and the redeem script.

Abstract: A specialized network (“merchant”) node to facilitate fast distribution of blockchain transactions over a network of interconnected nodes, as subset of which are merchant nodes interconnected by an overlay network. The merchant node includes a memory storing an assigned portion of a distributed mempool structured as a distributed hash table, the distributed mempool containing pending transactions awaiting confirmation. The merchant node operates by receiving a transaction, including a transaction identifier; hashing the new transaction identifier to obtain a key; determining, using the key, whether the transaction is stored in the distributed mempool or not and, if not, then storing the transaction in the distributed mempool as a pending transaction; and sending the transaction to a set of nodes other than merchant nodes using peer-to-peer connections. The invention may be used in conjunction with the Bitcoin blockchain or an alternative.