Abstract: A computer-implemented method for connecting to a layered network. The layered network comprises a plurality of nodes arranged in an ordered set of layers. The ordered set of layers comprises, in order, a core layer comprising a set of core nodes, a second layer comprising a set of second nodes, and one or more outer layers each comprising a respective set of outer nodes. Each core node is connected to at least one other core node. The method is performed by a connecting node and comprises connecting to the network according to a connection protocol. The connection protocol requires that each node must connect to at least one node of a preceding layer, and each outer node must also connect to at least one core node.

Abstract: A method (300) and system (1) of determining a common secret for two nodes (3, 7). Each node (3, 7) has a respective asymmetric cryptography pair, each pair including a master private key and a master public key. Respective second private and public keys may be determined based on the master private key, master public key and a deterministic key. A common secret may be determined at each of the nodes based on the second private and public keys. In one example, a node (3, 7) may determine the common secret based on (i) a second private key based on the node's own master private key and the deterministic key; and (ii) a second public key based on the other node's master public key and the deterministic key. The invention may be suited for use with, but not limited to, digital wallets, blockchain (e.g. Bitcoin) technologies and personal device security.

Abstract: A method comprising, at an attesting node of a network: receiving a sequence of data items from one or more client nodes of the network, determining an order of the sequence of data items, and attesting to the order by: including an indication of a respective set of one or more of the data items in each of a series of blockchain transactions. Each successive transaction comprises a respective input pointing to an output of the respective preceding transaction, wherein the output of the respective preceding transaction comprises a locking script, and the input of the respective successive transaction includes an unlocking script comprising a respective signature based on a respective key in a series of keys. The respective signature in each successive transaction signs a portion of the respective successive transaction including at least the indication of the respective set of data items.

Abstract: A method performed in a layered network. The layered network comprises a core layer comprising one or more core nodes, one or more intermediate layers each comprising one or more intermediate layer nodes, and one or more outer layers each comprising one or more outer layer nodes. Each of the core nodes is a node of a blockchain network. One or more intermediate layer nodes are smart contracts nodes providing a smart contract service for maintaining the state of a smart contract. One or more outer layer nodes are client nodes of the smart contract service. The method included, by a smart contract node: recording a state of the smart contract in a record of the state maintained at the first smart contract node. In addition, at least a first transaction also recording the state is recorded on a blockchain of the blockchain network.

Abstract: A method performed in a layered network. The layered network comprises a core layer comprising one or more core nodes, one or more intermediate layers each comprising one or more intermediate layer nodes, and one or more outer layers each comprising one or more outer layer nodes. Each core node is a node of a blockchain network. At least some intermediate layer nodes are database nodes. At least some outer layer nodes are client nodes. Each database node stores at least part of a distributed database. The method includes, at a database node: receiving one or more update requests from one or more client nodes requesting to update a database entry; and for each update request, applying the update locally and/or forwarding to another database node.

Abstract: A computer-implemented method (and corresponding system) is provided, that enables or facilitates the execution of a portion of source code, written in a high-level language (HLL), on a blockchain platform. The method and system can include a blockchain compiler, arranged to convert a portion of high-level source code into a form that can be used with a blockchain platform. This may be the Bitcoin blockchain or an alternative. The method can include: receiving the portion of source code as input; and generating an output script comprising a plurality of op_codes. The op_codes are a subset of op_codes that are native to a functionally-restricted, blockchain scripting language. The outputted script is arranged and/or generated such that, when executed, the script provides, at least in part, the functionality specified in the source code.

Abstract: A method of managing an overlay network overlaid on data-storage transactions of a blockchain, whereby data content of the overlay network is stored in payloads of the data-storage transactions and overlay-layer links are defined between the data-storage transactions. The method comprises identifying a graph structure of the overlay network, wherein nodes corresponds to different ones of the data-storage transactions and edges correspond to the links. Each node is associated with a respective first key for signing an input of a child data-storage transaction to authorise writing the child to the blockchain. The method further comprises using a child key derivation, CKD, function to determine a hierarchical set of second keys having the same graph structure as the overlay network, wherein the second keys enable an additional function other than signing inputs of the data-storage transactions.

Abstract: The invention provides a method and corresponding system for controlling a blockchain transaction output and/or specifying the recipient of the output. It also provides a method of controlling and/or generating an electronic communication. The invention is a blockchain-implemented solution, which may or may not be the Bitcoin blockchain. In a preferred embodiment of the invention, the method may comprise the step of sending an electronic notification to a notification address which is provided as metadata within an unlocking script of an input of a transaction (Txi) on a blockchain. The unlocking script is provided in order to spend an output from a further transaction (Tx2) on the blockchain. The input of the transaction (Txi) and/or the output of the further transaction (Tx2) may be associated with a tokenised asset represented on, or referenced via, the blockchain.

Abstract: A computer-implemented method of using blockchain transactions to issue one or more single-uses tokens for use by one or more respective token redeemers, wherein the method is performed by a token issuer and comprises: generating a token transaction, wherein the token transaction comprises: one or more token outputs, wherein each token output comprises token data representing a respective single-use token, wherein each single-use token is associated with a respective spendable output of the token transaction, and wherein a respective validity of each single-use token is conditional on the respective spendable output being present in an unspent transaction output set of a blockchain; and one or more inputs, wherein at least a first one of the inputs comprises a signature linked to a first public key of the token issuer; and transmitting the token transaction to one or more nodes of a blockchain network to be recorded in the blockchain.

Abstract: A computer-implemented method of pseudo-randomly selecting game elements for use in playing a game. An oracle obtains: a set of seed data items, the set of seed data items comprises one or more user seed data items generated by a respective user; a sequence of public keys; and a list of game elements. A total number of public keys corresponds to a total number of game elements. The oracle generates a first output of a game transaction. The first output comprises the sequence of public keys and a script configured to generate at least one pseudorandom number based on the set of seed data items. The script is configured to generate a list of the public keys based on the at least one pseudorandom number. An order of public keys in the list of public keys differs compared to an order of public keys in the sequence of public keys.

Abstract: A method and devices for securely and privately generating a threshold vault address and distributed individual key shares reliant upon individually selected polynomial functions, without revealing the key shares and without ever reconstructing the private key. A digital asset stored at the threshold vault address may be used as an input to a transaction through generating a digital signature corresponding to the threshold vault address. Methods and devices are described for collaboratively generating the digital signature without reconstructing the private key or revealing individual key shares. Methods and devices are described for refreshing the distributed private key shares.

Abstract: A computer-implemented method (900) and system (1) for verifying the integrity of a computer software for installation using a distributed hash table (13) and a peer-to-peer distributed ledger (14). This may be the Bitcoin blockchain or an alternative implementation. The method includes determining (910) a metadata associated with a transaction record stored on the peer-to-peer distributed ledger (14). An indication of an entry stored on the distributed hash table (13) may be determined (920) from the metadata. The method further includes determining (930) a third hash value based on the computer software and determining (940) a fourth hash value from the entry on the distributed hash table (13). The method further includes comparing (950) the third hash value and the fourth hash value and verifying (960) the integrity of the computer software based on the comparing of the third hash value and the fourth hash value.

Abstract: A data structure embodied in one or more blockchain transactions has a plurality of nodes, each node embodied as a hash value contained in a blockchain transaction of the one or more blockchain transactions; and a plurality of directional edges plurality of nodes comprises leaf nodes and non-leaf nodes. In a first aspect, at least one of the non-leaf nodes has at least one child leaf node and at least one child non-leaf node, the hash value of the at least one non-leaf node being a hash of a concatenation of the respective hash values of the child leaf node and the child non-leaf node. In a second aspect, a first of the non-leaf nodes has a different number of child nodes than a second of the non-leaf nodes. In a third aspect, a first of the leaf nodes has a different level than a second of the leaf nodes.

Abstract: The invention provides a secure method for exchanging entities via a blockchain. The invention incorporates tokenisation techniques, and also techniques for embedding metadata in a redeem script of a blockchain transaction. Embodiment(s) provide a method of: generating a first script, the first script comprising: a first set of metadata associated with a first invitation for the exchange of a first entity by a first user, the first set of metadata comprising an indication of the first entity to be offered for exchange and a first location condition for the exchange, a first user public key (P1A) associated with the first user, wherein the first user public key (P1A) is part of an asymmetric cryptographic pair comprising the first user public key (P1A) and a first user private key (V1A).

Abstract: A public key may be recorded on the blockchain by a certificate authority in such a manner that any third party may quickly and easily verify that the public key is certified by the certificate authority and that the certification has not been revoked. The certificate authority may be able to revoke the certification nearly instantaneously, and/or may be able to simultaneously certify a new key for the same entity while revoking the old key. The verification may be incorporated into a new transaction so that there is no gap between reliance on the certificate and the verification of its validity. In some cases, each transaction in which the certificate is used may also serve as linked certificate transaction that renews the certificate to enable a subsequent use.

Abstract: A blockchain payment channel is effected based on a series of spending transactions exchanged between parties, in which each transaction of the series of spending transactions has a future lock time, before which it cannot be committed to the blockchain, and comprises at least two spendable transaction outputs having respective digital asset values. At computer equipment of the party, a previous transaction of the series of spending transactions is received, and a function is applied to one or more function variables contained in the previous transaction to at least partially determine the current transaction. A portion of the current transaction is cryptographically signed, the signed portion comprising the at least two spendable transaction outputs, using a private key counterpart to the public key of the party, thereby computing a transaction signature for inclusion in the transaction input of the current transaction.

Abstract: A computer-implemented method of pseudo-randomly generating winning game elements for use in playing a game. An oracle obtains: a set of seed data items, the set of seed data items comprising one or more user seed data items; and a sequence of first public keys, each first public key representing a respective one of the set of first game elements. The oracle generates an output of a game transaction that comprises an output script. The script comprises the sequence of at least some of the first public keys, and wherein the output script is configured to, when executed, generate at least one pseudorandom number, the pseudorandom number being based on the set of seed data items, and to select a winning key, the winning public key being the public key at a position in the sequence of first public keys corresponding to the pseudorandom number.

Abstract: A computer-implemented method of generating a transaction associated with a blockchain, the transaction being for distributing amounts of an allocation of a digital asset, wherein the allocating party is associated with an allocating public key linked with the allocation, and wherein each recipient party is associated with a respective ownership public key. The method comprises obtaining a respective ownership public key of each of the one or more recipient parties. For each of the one or more recipient parties, a respective payment public key is generated based on (i) the ownership public key associated with that recipient user, and (ii) the allocating public key. The transaction comprises one or more output scripts, each output script configured to transfer a respective amount of the allocation to a respective payment address, the respective payment address being based on the respective payment public key.

Abstract: A blockchain payment channel based on a series of spending transactions exchanged between parties, in which: a funding transaction, committed to a blockchain, comprises at least one spendable transaction output locked to at least two public keys of the parties, wherein the funding transaction contains or otherwise evidences a function for at least partially computing the series of spending transactions. A previous transaction of the series is received at computer equipment of one of the parties. The function contained or otherwise evidenced in the funding transaction is used to at least partially compute the current transaction. A portion of the current transaction is cryptographically signed by the party, the signed portion comprising the at least two spendable transaction outputs, using a private key counterpart to the public key of the party, thereby computing a transaction signature for inclusion in the transaction input of the current transaction.

Abstract: Contributions to a work by contributors having respective levels in a defined hierarchy are recorded in one or more blockchain transactions. One or more lower-level contributors provide, to a higher-level contributor, one or more lower-level contributions respectively, and the higher-level contributor provides a higher-level contribution responsive to the one or more lower-level contributions. A higher-level contributor transaction comprises one or more inputs, which in turn comprise: one or more pointers to one or more spendable outputs of one or more lower-level contributor transactions and one or more transaction signatures. The transactions contain contributions commitments which, together with the one or more pointers, represent the relationship between the higher-level contributor and the lower-level contributors within the defined hierarchy. The one or more transaction signatures prove that relationship.