Abstract: A method for enabling a verifying party to verify an identity of a target comprising a target party or device. The method comprises, in a set-up phase, by a party other than the verifying party: inputting a set of one or more challenges into a PUF module comprising a physically unclonable function, PUF, in order to generate a respective set of one or more responses based on the PUF; and storing a respective response data record for each of the set of responses in a data store external to any equipment of the target party or verifying party, the data store either being part of third party computer equipment or being a public peer-to-peer publication medium. The response data records are thus made available to the verifying party to verify the identity of the target in a subsequent verification phase.

Abstract: Methods and devices to enable the splitting of storage and validation functions from mining function in a blockchain network. The storage and validation nodes create candidate blocks and collect block rewards from successfully mined blocks. The mining nodes provide hash power for mining the candidate blocks and received resources from the storage and validation node for successful mining of a candidate block. Atomic exchange mechanisms are described for preventing loss and fraud and minimizing the use of bandwidth by mining nodes.

Abstract: A computer-implemented method of validating token transactions, wherein the validating entity has access to a token mint transaction and/or a token setup transaction, wherein the token mint transaction comprises cryptographic minting data, and mints an initial amount of the tokens, wherein the token setup transaction comprises the minting data certified by the token issuer, and wherein the method is performed by a validating entity and comprises: obtaining a target token transaction comprising one or more token inputs and one or more token outputs; and validating the target token transaction, wherein said validating of the target token transaction comprises: verifying that each token input of the target token transaction comprises the minting data, and/or verifying that each token input of the target token transaction references a respective token output of either the token mint transaction or a previously validated token transaction that can be traced back to the token mint transaction.

Abstract: The invention provides methods and systems which enable additional functionality to be inserted into blockchain scripts with ease and in an effective and manner. According to one embodiment, the invention provides a blockchain-implemented method comprising the steps of arranging a plurality or selection of scripting language primitives to provide, upon execution, the functionality of a high-level scripting language primitive, wherein the scripting language is associated with a blockchain protocol; inserting the plurality of scripting language primitives at least once into a script; and inserting the script into blockchain transaction (Tx). The high-level scripting language primitive may perform, for example, an arithmetic operation such as multiplication or division. The scripting language primitives may be called op-codes, words or commands, and are native to the scripting language. The scripting language may be Script, and the blockchain protocol may be a version of the Bitcoin protocol.

Abstract: A comprising, by target computer equipment of a target party: obtaining a cryptographic key derived from a response generated by PUF module comprising a physically unclonable function, PUF, the response having been generated by the PUF module based on the PUF in response to a corresponding challenge input to the PUF module, wherein key information comprising the cryptographic key or a corresponding public key is also made available to a verifying party; from an issuing party, receiving a computation request specifying the computation to be performed; in response to the computation request, performing the computation in order to generate a computation result; signing a message comprising the computation result with the cryptographic key; and making the signed message available to the verifying party by sending the signed message to be recorded on a blockchain.

Abstract: A method of transferring control of a digital asset (2) is disclosed. The method comprises distributing shares dAi of a first private key dA of an elliptic curve cryptography (ECC) system among a plurality of first participants (4). The first private key is accessible by means of a first threshold number (6) of shares dAi of the first private key, and is inaccessible in the absence of the first threshold number of shares, and access to the digital asset (2) is provided by digital signature of a first encrypted message with the first private key. Shares of a deterministic key Dk of the cryptography system are distributed among the either the first participants or a plurality of second participants, wherein the deterministic key is accessible by means of a second threshold number of shares of the deterministic key, and is inaccessible in the absence of the second threshold number of shares.

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: A system for performing transaction mixing between a plurality of users on a blockchain is provided. The blockchain may be, for example, the Bitcoin blockchain. The system is configured to carry out the steps of: (i) preparing a first commitment transaction arranged to transmit control of a resource from a source address of a first user to a receiving address of a second user; (ii) preparing a second commitment transaction arranged to transmit control of a resource from a source address of the second user to a receiving address of a further user; (iii) preparing a further commitment transaction arranged to transmit control of a resource from a source address of the further user to either: (a) a receiving address of the first user; or (b) a receiving address of a yet further user and repeating step (iii) until option (a) is performed to complete a transaction chain; and (iv) executing the transaction chain. At least one of the users is randomly chosen from the plurality.

Abstract: In one aspect, the present disclosure proposes methods, devices and systems for partitioning a request associated with a digital asset into an arbitrary number of transactions. The partitioning is based on knowing or obtaining a maximum number of outputs allowed for a request and an arbitrarily selection of a possible integer partition of an arbitrarily selected integer. The randomly selected integer partition then forms the basis for determining the number of transactions and UTXOs, so that a digital asset value can be arbitrarily split across the determined UTXOs before being stored on a public blockchain. In another aspect, the present disclosure proposes methods, devices and systems for arbitrarily distributing a digital asset value associated with a request across an arbitrarily determined number of transactions. This is based on an arbitrarily selected number of transactions, and a maximum number of outputs allowed for each request.

Abstract: A computer-implemented method of generating a second transaction for a blockchain. The blockchain comprises a first transaction comprising a first token and a first output transferring an amount of a digital asset between a second party and a first party. The first token represents a first amount of a token asset other than the digital asset, the second transaction is for transferring a second token representing a second amount of the token asset from a first party to a third party. The method is performed by the first party and comprises generating the second transaction. The second transaction comprises a first input configured to unlock the first output of the first transaction, and a first output comprising the second token. The second token comprises data representing the second amount of the token asset, the second amount being less than the first amount.

Abstract: A computer-implemented method of generating a digital signature, wherein the method is performed by a signing party and comprises: obtaining a first message; generating an ephemeral private key based on at least a hash of an external data item; and generating a first signature comprising first and second signature components, wherein the first signature component is generated based on an ephemeral public key corresponding to the ephemeral private key, and wherein the second signature component is generated based on the first message, the ephemeral private key, the first signature component and a first private key.

Abstract: A computer-implemented method of generating a share of a digital signature, wherein each participant has a respective share of a first shared private key, wherein the method is performed by a first participant and comprises: obtaining a first message; generating a first data item based on at least a hash of a first external data item; generating a first ephemeral private key share of an ephemeral private key based on the first data item and a respective data item generated by each other participant; generating an ephemeral public key corresponding to the ephemeral private key; generating a first signature share based on the first message, the first ephemeral private key share, a first share of the first shared private key, and the ephemeral public key; and making the first signature share available to a coordinator for generating a first signature based on at least a threshold number of signature shares.

Abstract: For a first node, second common secrets common to the first node are determined. A second node, is determined at the first node based on a first private key of the first node and a first public key of the second node and is determined at the second node based on the first private key of the second node and the first public key of the first node. A third common secret common to the second node and a third node is determined for the second node. Shares of the first common secret known to the first node are encrypted at the first node. The encrypted shares are sent to the second nodes. Encrypted shares of the first common secret are received at the first node from the second node to enable each of the nodes to reach a threshold number of shares of the first common secret.

Abstract: A computer-implemented method of transmitting blockchain transactions to a blockchain network, wherein the method is performed by a first party and comprises: transmitting at least part of a blockchain transaction to an internet server via an internet service hosted by the internet server, wherein the internet server is configured to connect to one or more nodes of the blockchain network, and to transmit a blockchain transaction to the one or more blockchain nodes, wherein the transmitted blockchain transaction comprises the at least part of the blockchain transaction.

Abstract: A computer-implemented access method is provided. The method comprises the steps of: (i) submitting, to a blockchain (such as the Bitcoin blockchain), an access blockchain transaction addressed to a derived public key derived at least in part from a secret value and a public key; (ii) generating a verification public key based at least in part on the secret value and the public key; (iii) comparing the derived public key and the verification public key; and (iv) based on the comparison of step (iii): (a) allocating the at least one of the derived and verification public key as a further public key for verifying a further derived public key; and (b) granting access to a resource associated with at least one of the secret value and the derived public key.

Abstract: A computer-implemented method of generating a second public key based on a first public key using blockchain transactions. The method is performed by a first party and comprises generating an output script of a first blockchain transaction. The output script comprises a public key derivation script configured to, when executed alongside an input script of a second blockchain transaction, generate the second public key based on the first public key. The input script of the second blockchain transaction comprises the first public key. The method further comprises transmitting the first blockchain transaction to one or more nodes of a blockchain network for inclusion in the blockchain.

Abstract: This invention relates generally to blockchain implementations and is suited for, but not limited to, use with the Bitcoin blockchain. It can be used for the implementation of automated processes such as device/system control, process control, distributed computing and storage and others. The invention provides an event detecting, monitoring and/or counting mechanism. The event may be, for example, a vote, decision or selection which is made by a given entity. The invention provides a counting solution in which a computing resource, running simultaneously and in parallel to the blockchain, manages a loop-based operation. The computing resource continuously monitors the state of the blockchain as well as any other off-blockchain input data or source. The execution of the loop is influenced by the state of the blockchain. Each iteration of the loop that is executed by the computing resource is recorded in a transaction that is written to the blockchain. It is stored as a hash within the transaction's metadata.

Abstract: A computer implemented method of facilitating a consumption tax on a purchase of one or more goods and/or services by a buyer from a seller, wherein at least the buyer is a buyer-seller who makes an onward sale based on said goods and/or services. The method comprises, by the seller of the purchase, obtaining a first blockchain transaction that can be redeemed by a second blockchain transaction meeting either of two alternative conditions: a first condition requiring at least that the second blockchain transaction is signed with a cryptographic signature of the buyer, and a second condition requiring at least that the second blockchain transaction is signed with at least a cryptographic signature of a tax authority; and in response to receiving a payment of the consumption tax from the buyer, sending the first blockchain transaction to be recorded on a blockchain.

Abstract: A computer-implemented method of determining the validity of a token (T) associated with a quantity of cryptocurrency is provided. In some embodiments, the method comprises: a second user (B) receiving, over a communications network, a first transaction comprising a transfer of the token (T) from a first user (A) to the second user (B), querying a peer-to-peer distributed ledger to determine whether an authenticated transaction associated with the token (T) can be identified, wherein the authenticated transaction comprises a previous transaction associated with the token (T) and wherein the token (T) has been authorised and responsive to identifying an authenticated transaction, determining that the token (T) is valid.

Abstract: There may be provided a blockchain-implemented security method. It may be implemented using a blockchain network. Embodiments of the blockchain-implemented security method involve a first party and a second party. The blockchain-implemented security method generates a plurality of n cryptographic locks based on combinations of encrypted versions of a first plurality of n secrets generated by the first party and encrypted versions of a second plurality of n secrets generated by the second party. One secret belonging to the first plurality of n secrets generated by the first party is randomly selected. And a cryptographic key that unlocks a particular cryptographic lock of the plurality of n cryptographic locks is generated, wherein the particular cryptographic lock corresponds to the randomly selected one secret belonging to the first plurality of n secrets generated by the first party.