Abstract: A method of enabling knowledge proof in a blockchain transaction is disclosed. The method comprises sending, from a verifier to a prover, a blockchain transaction redeemable by means of data including (i) first data (y) based on a combination of an ephemeral key (r), second data (c) and a private key of a public-private key pair of a cryptography system, wherein the public key (v) is based on an integer generator raised to a first power, wherein the first power is based on the private key, and wherein knowledge of the private key is required in order to determine the ephemeral key from the first data, and (ii) third data (x) based on the integer generator raised to a second power, wherein the second power is based on the ephemeral key.

Abstract: A computer-implemented security method is provided. The method may be implemented on one or more blockchains, such as the Bitcoin Cash blockchain.

Abstract: The present disclosure proposes methods and devices for facilitating IP transaction involving digital assets over the Internet directly based on IP addresses for entities. The aspects and embodiments of the present disclosure enable secure IP address transactions by ensuring that the public key of the recipient is never used in the generation of payment destination addresses, thereby making message replay and MITM attacks extremely hard to implement by an attacker. Furthermore, the aspects and embodiments ensure that the payment destination addresses for digital assets are based on new or single use private as well as public keys that are computed or provided based on the public key for the recipient and are specific to a given transaction.

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 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: Techniques described herein may be utilized to serialise and de-serialise arithmetic circuits that are utilized in the execution of computer programs. The arithmetic circuit may be utilized to build a Quadratic Arithmetic Problem (QAP) that is compiled into a set of cryptographic routines for a client and a prover. The client and prover may utilize a protocol to delegate execution of a program to the prover in a manner that allows the client to efficiently verify the prover correctly executed the program. The arithmetic circuit may comprise a set of symbols (e.g., arithmetic gates and values) that is compressed to produce a serialised circuit comprising a set of codes, wherein the set of symbols is derivable from the set of codes in a lossless manner. Serialisation and de-serialisation techniques may be utilized by nodes of a blockchain network.

Abstract: Systems and methods are disclosed for establishing information on a state of a machine-executable contract in the context of unspent transactions (UTXOs), blockchain and deterministic finite automaton implementation of contracts, and determination of states within those. Stages of a method include determining information of interest and codes or tags identifying that information, constructing metadata associated with those codes or tags, and combining the metadata with a public key for an agent associated with the information. ScriptPubKey values of each script are used to provide keys for constructing a database and mapping the keys from the scriptPubKey values, linked to the information. A derivation of script hash addresses from the scriptPubKey values is used to populate a digital wallet. A search and match algorithm is used to find UTXOs with matching script hash addresses on a blockchain. The database is populated with UTXOs that match the script hash addresses and keys to complete the combinations.

Abstract: The invention relates to distributed ledger technologies such as consensus-based blockchains. Computer-implemented methods for a self-replicating smart contract with termination condition are described. The invention is implemented using a blockchain network, which may be, for example, a Bitcoin blockchain. A first transaction to validate is received at a node in a blockchain network. The first transaction includes a first script that, as a result of being executed, causes the node to at least obtain a first set of field values of the first transaction, with the first set of field values including a third script, and obtain a second set of field values of a second transaction, with the second set of field values including a copy of the second script. A second transaction is obtained.

Abstract: The disclosure relates to a blockchain-implemented system and method of controlling the transmission and/or distribution of digital content. A first user is associated with a deposit quantity of cryptocurrency at a common address. A first node associated with the first user sends a request to the second node to provide an episode of digital content from a series of digital content; determines a payment transaction to transfer a payment quantity of cryptocurrency to the second user, wherein the payment quantity is based on a quantity of episodes of digital content in the series; and signs and sends the payment transaction to a second node. The second node associated with the second user: receives the request and the payment transaction; verifies the payment transaction; and based on the result of verifying: provides access to the episode of digital content to be available to the first node; and co-signs and sends the payment transaction to a distributed ledger.

Abstract: A computer implemented system and a method for providing user related data, such as reputational information, on users of a blockchain involved in transactions is detailed. The method includes an approach for evaluating fulfilment of transactions, particularly in the context of contracts, and then providing a record of that on the blockchain through reputational information. As a result, at a late time, this reputational information can be retrieved. Similar reputational information for other transactions can be retrieved and linked to the same user, for instance based on the use of a hash of the master public key for a user. Aggregate reputational information can be computed from the pieces of reputational information retrieved.

Abstract: The computer-implemented invention provides a method and corresponding system for controlling access to and/or use of an internet-enabled resource. The invention uses an electronic ledger such as, for example, the Bitcoin blockchain. The resource may be an IoT device or system. Access to the resource is permitted or enabled upon provision of a cryptographic key e.g. a private key which corresponds to a public key which has been stored in memory. In one embodiment, the public key is stored in a DHT. Access to the resource is prevented or disabled by removing the public key from memory, and using a redeem script of a second blockchain Transaction to spend a tokenised output of a first blockchain Transaction. The second transaction detokenizes the token (or ‘coloured coin’) contained within the first Transaction. In order to prevent further access to the resource, an encrypted message is sent to the internet-enabled resource, wherein the message communicates a public key and the redeem script.

Abstract: A method and system of recording multiple transactions between a multiple of users on a blockchain (9), including a first transaction (22) from a first user (5) to a second user (7) and a second transaction (24) from the second user (7) to the first user (5). The blockchain may be, for example, the Bitcoin blockchain. The method may include receiving (110) a first request from a first node (15) associated with the first user (A) to transfer a first quantity of cryptocurrency associated with the first transaction (22) and receiving (120) a second request from a second node (17) to transfer a second quantity associated with the second transaction (24). The first transaction (22) is conditional on receiving (120) the second request and the second transaction (24) is conditional on receiving (110) the first request. The method also includes verifying (130) the first request and second request that includes determining both the conditional steps of receiving the first request and second request are satisfied.

Abstract: Embodiments of the present disclosure provides protocols, methods and systems which provides advantages such as the resistance of centralisation of mining on a blockchain network, preferably a Proof-of-Work blockchain. A method in accordance with an embodiment may comprise generating a plurality of non-parallelisable challenges (or “puzzles”) and allocating one of said plurality of challenges to each miner on the network. The miner uses an inherently sequential (non-parallelisable) algorithm to find a solution to his allocated challenge. The challenges are generated by a committee of nodes, and a new set of challenges is generated for each block.

Abstract: The present disclosure provides methods and systems for ensuring the security of a blockchain and associated network, and for enabling the establishment of consensus regarding the state of the blockchain. A method of the disclosure may be implemented by one or more nodes on a blockchain network, using a non-parallelisable algorithm to calculate an output based on a computational difficulty parameter, a hash of at least one blockchain transaction; and/or a hash of at least one blockchain block header. The non-parallelisable, inherently sequential algorithm comprises at least one of the following operations or a combination thereof: a recursive operation, a modular exponentiation and/or a repeated squaring operation.

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 method of creating, redeeming and transferring tokens associated with tokens on a peer-to-peer distributed ledger. The method includes including metadata associated with the token in a redeem script, wherein the redeem script is associated with a transaction of cryptocurrency on the peer-to-peer distributed ledger. One aspect of the invention provides a method of issuing and/or transferring a token, comprising the steps of generating a blockchain transaction (Tx) having an output (TxO) related to a quantity of cryptocurrency such as Bitcoin, and a hash of a redeem script. The redeem script comprises metadata which in turn comprises a token. The token is a representation of, or a reference to, a tokenised entity. The redeem script also comprises at least one (preferably two or more) public cryptographic keys. The metadata is provided in the redeem script at a location which is designated in the underlying blockchain protocol as a location for a cryptographic key.

Abstract: A computer-implemented method and system for encrypting an executable of a computer software for installation using a distributed hash table and a peer-to-peer distributed ledger. This may be the Bitcoin blockchain or an alternative implementation. The method may include determining a generator value.

Abstract: A method of encrypting data at an electronic device where the electronic device is associated with a key device. Each device is associated with an asymmetric cryptography pair, each pair including a first private key and a first public key. Respective second private and public keys may be determined based on the first private key, first public key and a deterministic key. A secret may be determined based on the second private and public keys. The data at the electronic device may be encrypted using the determined secret or an encryption key that is based on the secret. Information indicative of the deterministic key may be sent to the key device where the information may be stored.

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: This invention relates generally to blockchain implementations and is suited for, but not limited to, use with the Bitcoin blockchain. The invention relates to a technical solution for managing a voting, counting, selection and/or decision making process. 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.