Abstract: A computer-implemented method is described for enabling recovery of one or more digital assets held on a blockchain by a user under a public key Pk after a corresponding private key Sk for accessing the one or more digital assets is lost. The computer implemented method comprises setting access for the one or more digital assets held on the blockchain under the public key Pk and accessible using the corresponding private key Sk of the user such that the one or more digital assets are also accessible using a private key x shared by a congress on the blockchain network, the congress comprising a group of users on the blockchain network, each member of the congress having a private key share xi, the private key share xi to be used in a threshold signature scheme in which at least a threshold of private key shares must be used to generate a valid signature through the combination of partial signatures of the congress to access the one or more digital assets on behalf of the user.

Abstract: There may be provided a computer-implemented method. It may be implemented using a blockchain network such as, for example, the Bitcoin network.

Abstract: The invention relates to method for a node of a blockchain network, the computer-implemented method comprising receiving or generating, at a node, data for distribution in the blockchain network, said node having a plurality of interfaces, said data corresponding to an object such as a transaction or a block. The transaction can be a Bitcoin transaction for recordal in a blockchain. The method determines a correlation matrix having correlation coefficients representing the correlation between data processed at each interface of said node. From the correlation matrix a correlation index for each interface is determined. A threshold or indicator is calculated and data or objects such as Bitcoin transactions are relayed from nodes via interfaces according to a set of correlation coefficients of interface receiving the data. An indicator or threshold can derived from the correlation matrix and data is relayed if the correlation between the receiving interface and the other interface is lower than the indicator.

Abstract: A computer-implemented method includes: storing an encryption public key that is associated with a group of nodes, each node in the group associated with a private key share, the private key shares associated with a threshold private key reconstruction scheme for the group to allow an encryption private key associated with the encryption public key to be determined from at least a threshold of the private key shares; iteratively obtaining a plurality of indicators provided by a plurality of nodes of the group, each of the indicators representing one of an encryption private key share or a dummy signal; and identifying the encryption private key by iteratively: i) selecting a subset of the indicators; ii) calculating a possible shared secret; and iii) evaluating each possible shared secret against the encryption public key to determine whether the possible shared secret is the encryption private key. The invention is suited for implementation on a blockchain.

Abstract: The invention provides a novel and advantageous solution for controlling or influencing use of and/or access to a resource. This resource may be a device, such as an IoT (Internet of Things) device or a process. The invention is implemented via a distributed ledger (blockchain). This may be the Bitcoin blockchain or some alternative blockchain platform/protocol. In an illustrative embodiment, the controlled resource is a parking meter.

Abstract: Methods and devices for two nodes to authenticate each other as credentialed by a group of autonomous specialized nodes, without involving the group or involving a centralized certificate manager or authenticator. The method may involve a first node and a second node using bilinear pairing operations involving their respective identifiers and secret points to derive the same session key. Provided the secret points and identifiers were obtained from the group using the group private key, the bilinear pairing operation leads to generation of the same session key at each of the two nodes, thereby authenticating their respective credentials and enabling trusted communications between the two nodes.

Abstract: A blockchain-implemented transaction from an originator node is to be broadcast. The originator node is communicatively coupled to proxy nodes. The method, implemented by a proxy node, includes: receiving a transaction including an input taking x+r units of computing resources, an output providing x units to the output address and another output providing d+r units to a 1-of-n multi-signature address unlockable by any one of a set of private keys associated the proxy nodes. The proxy node selects a quantity of computing resources, t units, to be allocated to the proxy node for broadcasting the transaction and having it included in the blockchain and generates a further transaction taking d+r units sourced from the multi-signature address and an output providing t units to the proxy node. The proxy node broadcasts both transactions timed to permit their inclusion in the same block of the blockchain.

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: Computer-implemented systems and methods are detailed for establishing information on states of a machine executable contract, for instance in the context of unspent transactions (UTXOs), blockchain and deterministic finite automaton (DFA) implementation of contracts and the determination of states within those. The stages can include determining the information of interest and the codes or tags identifying that information, constructing the metadata associated with those codes or tags, combining that with a public key for an agent that will be associated with the information. The scriptPubKey values of each script may be used to provide the keys for use in constructing an external database and more specifically mapping the keys from the scriptPubKey values, linked to the information of interest. To obtain the other half of the combination, there is a derivation of the script hash addresses from the scriptPubKey values, with those being used to populate a digital wallet.

Abstract: A system and method for providing reputational information on users involved in transactions is detailed. The method includes evaluating fulfilment of transactions, particularly in the context of contracts, and providing a record of that on a blockchain through reputational information, which can be retrieved later. Similar reputational information for other transactions can be retrieved and linked to the same user, based on a hash of a master public key for a user. Aggregate reputational information can be computed from pieces of reputational information retrieved. The evaluation and record provision can be implemented using a deterministic finite automaton (DFA). For each user involved in each contract, the DFA not only configures and allows for implementation of the contract, but also considers the extent of fulfilment of the contract's terms. The DFA generates reputational information in relation to each user in each contract, and this reputational information is published to and stored on the blockchain.

Abstract: A method and devices for verifying a digital resource by a plurality of node devices in a blockchain network. The plurality of nodes have respective private key shares, where a collective private key of a collective private-public key pair is based on a set of the respective private key shares, and where each node has a nodal private-public key pair. The digital resource may be encrypted using a digital resource crypto public key, the digital resource crypto public key including combination of a nodal public key and a collective public key. The digital resource may be submitted to a repository system by broadcasting a commitment transaction and a subsequent reveal or rescind transaction of a commitment channel, the commitment channel formed between a respective node and a principal node. Decrypting the encrypted digital resource is based on retrieving private key share contributions from the plurality of nodes participating in verifying the digital resource.

Abstract: A method of propagating data packets in a network of nodes is disclosed. The method, implemented at one of the nodes, includes: generating at least one data packet of a first type; collecting a set of data packets of the first type during a first time period, the set including the at least one generated data packet and at least one data packet of the first type received from one or more first nodes in the network; and for each data packet in the set: randomly select two or more neighbouring nodes connected to said one of the nodes; transmit, to each of the two or more selected neighbouring nodes: the data packet, wherein the two or more selected neighbouring nodes are configured to relay the data packet to one or more second nodes in the network using a mode of data propagation that is arbitrarily selected for that neighbouring node. The invention is particularly suited for implementation on a blockchain network such as, for example, the Bitcoin blockchain.

Abstract: The invention relates to blockchain technologies such as the Bitcoin blockchain. The invention uses a novel technique to decompose the functionality of a blockchain transaction script into several chunks or functional parts, and to use the output of a chunk as the input of the next chunk. Advantageously, this allows the blockchain to be used for ever complex tasks and computations while minimising script size, and also provides a novel architecture for the distributed execution of computational processes.

Abstract: Embodiments of the invention provide enhanced security solutions which are enforced through the use of cryptographic techniques. It is suited for, but not limited to, use with blockchain technologies such as the Bitcoin blockchain. Methods and devices for generating an elliptic curve digital signature algorithm signature (r, w) are described.

Abstract: An implementation of the present application provides a computer—implemented method to increase the security of a blockchain—implemented transaction, the transaction including participation from a plurality of participating nodes, each participating node participating as a message originator, selector, and propagator. The method, implemented at a participating node, includes: receiving ciphertext from a prior node and determining whether the participating node is a selector node for said ciphertext received from the prior node. When the participating node is the selector node for said ciphertext, the method includes selecting a subset of said ciphertext, decrypting the selected subset of said ciphertext to provide opted ciphertext and transmitting said opted ciphertext to the next node. When the participating node is other than the selector node for said ciphertext, the method includes decrypting said ciphertext received from the prior node and transmitting the decrypted ciphertext to the next node.

Abstract: The invention relates to method for adjusting the minimum and maximum number of peer nodes that a node on the blockchain network will connect with. The adjustment takes in to account the bandwidth and processing capability of the node. Bandwidth capacity of a node is determined based on a maximum data amount processable by the node over a time period. Data is monitored passing through interfaces of the node, to and from peer nodes, and a profile factor of the node is determined from the difference between the input data to output data. Over a plurality of time periods monitoring said data the data analysed is used to set a minimum number of peer nodes and a maximum number of peer nodes connectable to the node according to said monitored data and the maximum number of peers connectable to the node. The method enables a node to adjust the number of connections according to performance limitation factors, such as bandwidth availability and processing performance.

Abstract: The invention provides a generic operating system for coordinating, controlling and/or influencing the activities of a device. The invention is implemented using a blockchain platform with which the operating system is arranged to interact. The blockchain may be the Bitcoin blockchain. In a preferred embodiment, the device is an Internet of Things (IOT) device. The invention provides a computer-implemented control system and corresponding method for controlling a device, the system comprising a device configured for wireless communication with a network and having an IP address and a public-private key cryptographic key pair associated with the device; a software-implemented control component arranged to monitor the state of a blockchain network and/or transmit blockchain Transactions to the blockchain network; and a set of instructions arranged for execution by the control component to control the functionality of the device.

Abstract: The invention relates to blockchain technologies such as the Bitcoin blockchain. The invention uses a novel technique to decompose the functionality of a blockchain transaction script into several chunks or functional parts, and to use the output of a chunk as the input of the next chunk. Advantageously, this allows the blockchain to be used for ever complex tasks and computations while minimising script size, and also provides a novel architecture for the distributed execution of computational processes.

Abstract: The computer implemented invention provides a method, corresponding systems and arrangement within a network for detecting changes in the topology, ordering those changes by occurrence and constructing a new topology reflecting the changes. The invention addresses problems with keeping the knowledge of the network topology at each network node current, particularly when the network topology is dynamic, i.e. when links fail and recover at arbitrary times. The topology updating is event driven, as it is activated when some change in the network, particularly with nodes and links occurs. Events cause topology changes to be reported to other nodes in the network. Timestamping of messages allows the messages to be correctly applied as the most recent update or discarded. An algorithm is provided that allows each merchant node to maintain a correct view of the network topology despite link and node failures.