nChain Holdings Limited

A method of encrypting data is disclosed. The method comprises determining, at a first node associated with a first public-private key pair of a cryptography system having a first private key (V A ) and a first public key (P A ), a common secret (S 1 ) common with the first node and a second node, wherein the second node is associated with a second public-private key pair of the cryptography system having a second private key (V B ) and a second public key (P B ). The common secret is determined on the basis of the first private key and the second public key, and the properties of the cryptography system are such that the common secret can be determined on the basis of the second private key and the first public key. An encryption key, based on the common secret, is determined for encryption of data (M), and the data is encrypted on the basis of the encryption key, wherein the step of encrypting data includes an exclusive or (XOR) operation.

A computer-implemented method ( 100 ) and system ( 1 ) for controlling the performance of a smart contract. The method includes storing a contract on or in a computer-based repository. The contract is associated with a licence between a first user (U1) and a second user (U2). The method further includes 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 comprises metadata that includes an identifier indicative of a location where the contract is stored. The method further includes querying a peer-to-peer distributed ledger (i.e. blockchain) to determine whether the transaction comprises at least one unspent output (UTXO). The method further includes, responsive to querying the peer-to-peer distributed ledger, determining whether to modify performance of the contract. The blockchain may be the Bitcoin blockchain.

The invention provides a system for searching a blockchain (e.g. Bitcoin) for data/content stored in one or more blockchain transactions, and accessing that data/content. It may be used in conjunction with a protocol for searching the blockchain. An embodiment of the invention can be arranged to enable a user to search for, access, view, write and/or retrieve a portion of data provided in at least one blockchain transaction (Tx), and also arranged to identify the at least one transaction (Tx) based on a transaction index (TX index ) comprising a transaction ID and a public key associated with the transaction (Tx). The system may comprise a search facility which is either provided within the blockchain search system; or arranged to interface and/or communicate with the blockchain search system. It may also comprise at least one cryptocurrency wallet.

Methods performed by a validation one or a sender one of a plurality of nodes implemented by computing devices in a network. The sender node sends, to the validation node, a request to transfer an amount of virtual currency from a sender account (associated with transaction receipts) to a recipient account. The request includes first copies of the receipts or references thereto. The validation node requests second copies of the receipts from at least two of the nodes, and receives the second copies from fewer than all of the nodes. The validation node determines whether the first copies have been tampered with by comparing the first and second copies to one another. When tampering has not occurred, at least one new receipt is generated indicating the amount has been transferred. Then, the at least one new receipt is forwarded to fewer than all of the nodes for storage.

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.

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.

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.

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. In another respect, the present disclosure proposes methods, devices and systems for generating or determining one or more public addresses associated with a given entity for use in blockchain transactions for the given entity, so that such addresses may be securely and correctly associated with the given entity, while maintaining anonymity of the entity's identity.

A method of making a decision on a blockchain is disclosed. First public keys are received from each of a plurality of participants (A, B, C), wherein each first public key represents a possible selection by a participant and is related to a corresponding first private key by a cryptographic operation having a homomorphic property. The first public keys are combined to generate second public keys, wherein each second public key represents a possible decision based on a combination of possible selections. Third public keys, corresponding to the second public keys, are communicated to the participants. A voting blockchain transaction is generated (T c voting), wherein an input of the voting transaction is a script executable by means of a digital signature corresponding to a first private key of each of a plurality of the participants, wherein each first private key

This invention relates generally to distributed ledger technology (including blockchain related technologies), and in particular the use of a blockchain in implementing, controlling and/or automating a task or process. It may relate to the use of a blockchain or related technology for recording or representing the execution of a portion of logic. This portion of logic may be arranged to implement the functionality of a logic gate, or plurality of logic gates, such as AND, XOR, NOT, OR etc.. An embodiment of the invention may comprise the steps of: providing a blockchain Transaction comprising a redeem script for an output, wherein the redeem script comprises: i) a plurality of input parameters, wherein each input parameter is uniquely associated with a potential state of at least one data source supplied to an unlocking script of a further transaction arranged to spend the output; and wherein one of the input parameters which is a target output parameter; ii) logic arranged to provide a result based on: A) a calculation performed on the input