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.

Abstract: The invention relates generally to cryptographic techniques for secure processing, transmission and exchange of data. It also relates to peer-to-peer distributed ledgers such as (but not limited to) the Bitcoin blockchain. In particular, it relates to control solutions for identifying, protecting, extracting, transmitting and updating data in a cryptographically controlled and secure manner. It also relates to system inter-operability and the ability to communicate data between different and distinct computing systems.

Abstract: A computer implemented method for performing a transfer includes scanning entries in a distributed hash table (DHT) distributed across a first network, the DHT comprising entries including invitations to perform an exchange and links to transactions on a peer-to-peer (P2P) distributed ledger distributed across a second network, each invitation indicates entities to be exchanged and conditions for the exchange; determining a match between first metadata in a first invitation of a first entry from a first user and second metadata in a second invitation of a second entry from a second user; and broadcasting, over the second network, a first exchange transaction for inclusion on a P2P distributed ledger. The first exchange transaction may include an indication of a first quantity of a cryptocurrency to be transferred. A first output indicates a transfer of a first quantity of the first entity from the first user to the second user.

Abstract: Presented herein are one or more embodiments with novel techniques of: defining an asset comprising at least one private cryptographic key, each private cryptographic key being associated with an owner of the asset; generating a registry comprising at least one public cryptographic key; generating a smart contract comprising at least one rule relating to an automated generation of one or more blockchain transactions to enable a transfer to be made in respect of the asset; and using a computing agent to evaluate and/or execute the at least one rule of the smart contract. Thus, one benefit provided by the invention is that it allows the secure distribution of costs and income for an asset registered and maintained on the Blockchain, which, in turn increases the capability of such assets to meet the real-world needs of various entities such as the asset itself and investing parties.

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 secure method for exchanging entities via a blockchain is presented. The method comprises receiving, from a user over a communications network, an invitation to perform an exchange of entities; generating a redeem script comprising metadata; hashing the redeem script to generate a redeem script hash; sending the first script and the first script hash on a distributed hash table (DHT); and generating an invitation transaction comprising an output associated with an encrypted digital asset, and a hash of a script comprising an indication of entities to be exchanged, conditions for the exchange, and a public cryptographic key associated with the user.

Abstract: A computer-implemented method of accepting blockchain transactions, wherein the method is performed by a blockchain node of a blockchain network and comprises: generating a first transaction comprising a first output, the first output comprising a first output script; causing the first transaction to be published on the blockchain; receiving a second transaction comprising a second output, the second output comprising a second output script; and accepting the second transaction based on one or more conditions being met, wherein a first condition of said one or more conditions is that the second output script corresponds to the first output script.

Abstract: According to a first aspect, there is provided a computer-implemented method of cryptographically linking multiple documents, having multiple electronic signature requirements, via a sequence of blockchain transactions, the method comprising: computing document signature data satisfying a first signature requirement for an existing document, the first signature requirement defined in a blockchain transaction containing or referencing the existing document; wherein the document signature data signs a portion of a linking transaction containing or referencing a supplementary document, the linking transaction comprising an input for validly spending a spendable output of the blockchain transaction, whereby the document signature cryptographically links the supplementary document with the existing document; and wherein the signed portion comprises multiple outputs of the linking transaction; wherein a first of the multiple signed outputs is spendable and associated with the existing document, the signed portion d

Abstract: A computer-implemented method of recording an agreement between a requesting party and a confirming party on a blockchain, wherein the method is performed by the requesting party and comprises: generating a request transaction, wherein the request transaction comprises an input signed by the requesting party, and at least a first output comprising a cryptographic puzzle based on a first data item known to both the requesting and confirming parties, wherein the first data item represents the agreement; and causing the request transaction to be transmitted to one or more blockchain nodes.

Abstract: A computer-implemented method of generating a blockchain address based on a corresponding template output script of a blockchain transaction, wherein the blockchain address comprises a prefix component and a data component, and wherein the method is performed by a first party and comprises: generating a first blockchain address based on a first template output script, the first blockchain address comprising a first prefix component for identifying a first template output script, and a first data component representing one or more data items required to populate the first template output script; wherein the first prefix component is greater than one byte, and/or wherein the first data component is generated based on a plurality of data items required to populate the first template output script.

Abstract: A computer-implemented method of generating a seed for deriving one or more private keys, wherein the method comprises: obtaining one or more biometric readings; and for each of the one or more biometric readings: identifying a plurality of biometric features; generating a plurality of respective first binary representations, wherein at least some of the first binary representations are generated based on respective sets of the plurality of biometric features, and wherein the first binary representations preserves physical differences between the biometric features; and generating a respective second binary representation, each respective second binary representation being generated based on the respective first binary representations; wherein the method further comprises generating a seed based on the respective second binary representations.

Abstract: A computer-implemented method of storing a biometric vault system on a blockchain, wherein the biometric vault system comprises one or more biometric vaults, each biometric vault locking a respective secret value, and wherein the method comprises: obtaining at least one biometric reading; identifying a plurality of biometric features from the at least one biometric reading; generating one or more first biometric vaults; generating one or more blockchain transactions, wherein each blockchain transaction comprises a respective output comprising at least part of a respective second biometric vault, wherein each second biometric vault comprises a respective first biometric vault; and transmitting the one or more blockchain transactions to the blockchain network.

Abstract: A method of using a tree structure overlaid on a blockchain, wherein each node of the tree is a different transaction. The method comprises: inspecting the blockchain to identify at least part of the tree structure, including identifying a target child node which includes a record of a file in the respective payload of that node, and identifying a path comprising one or more edges back through the tree structure from the target child node to the root node. The method then comprises: A) for each edge along the identified path from target child node back to root node, checking that the respective child node is signed by a key associated with the respective parent node, and B) checking that a current instance of the file matches the record included in the target child node. The current instance of the file is verified at least on condition of these checks.

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.

Abstract: A computer-implemented includes sending a public key associated with a particular node in a cyclically-ordered set of nodes participating in a blockchain network to an initiator node; receiving, by the particular node from a node immediately previous to the particular node in the cyclically-ordered set, a first value based on public keys associated with each node from the particular node through to the initiator node; determining a locking value based on the first value and the public key associated with the particular node; and preparing using the locking value, a transaction arranged to transmit control of a resource from a source address associated with the particular node to a receiving address of a node immediately subsequent to the particular node. The control of the resource is to be transmitted responsive to satisfaction of an execution condition including supply of an unlocking value corresponding to the locking value.

Abstract: The invention presents a solution in which blockchain Transactions are created to implement the functionality of a logic gate. The invention may be implemented on the Bitcoin platform or an alternative blockchain platform. The transaction includes a locking script which comprises instructions selected so as to implement the functionality of a logic gate, such as the XOR gate. When the script is executed (because a second transaction is attempting to spend the output associated with the locking script) the inputs will be processed by the conditional instructions to provide an output of TRUE or FALSE. The inputs are pre-processed by one or more computing agents so that they are evaluated to TRUE or FASLE prior to being used as inputs to the script. The second transaction is transmitted to the blockchain network for validation and, if determined to be valid, it will be written to the blockchain. Validation of the second transaction can be interpreted as a TRUE output.

Abstract: A solution for controlling access to a resource such as a digital wallet implemented using a blockchain. Use of the invention during set-up of the wallet can enable subsequent operations to be handled in a secure manner over an insecure channel. An example method comprises splitting a verification element into multiple shares; determining a common secret at multiple nodes in a network; and using the common secret to transmit a share of the verification element between nodes. The shares can be split such that no share is sufficient to determine the verification element and can be stored at separate locations. Upon share unavailability, the share can be retrieved a location accessibility. For safe transmission of the share(s), the common secret is generated at two different nodes independently and used to generate an encryption key for encrypting at least one share of the verification element to be transmitted securely.

Abstract: Methods and systems are provided for storing, sharing, retrieving, writing and accessing data (content) on a blockchain such as, for example, the Bitcoin ledger. Embodiments of the method may comprise the step of processing at least one blockchain transaction (Tx) comprising: a protocol flag; at least one discretionary public key (DPK); and at least one discretionary transaction ID (DTxID). These are discretionary in the sense that they are not required as part of the underlying blockchain protocol but in accordance with present disclosure. The at least one transaction (Tx) also comprises a plurality of inputs, each input having: i) a parent public key (PPK) and ii) a signature (S) generated using the parent public key (PPK). Thus, the transaction forms an indexed node in a graph or hierarchical tree of logically associated nodes at least some of which include or reference portions of data. The nodes in such a tree can have multiple parents and/or children.