nChain Licensing AG

Techniques described herein may be utilised to implement methods and systems for lossless compression and serialisation of arithmetic circuits to a bit stream using compression techniques such as the arithmetic coding. An arithmetic circuit representing a smart contract may be compressed using arithmetic coding, thereby generating a compressed arithmetic circuit that can be stored or broadcast to a blockchain network using less computational resources (e.g., data storage resources) than would otherwise be needed to store the arithmetic circuit. The arithmetic circuit can be efficiently compressed using entropy coding based on the frequency of elements in the data structure, such as the arithmetic operator types. Instructions for de-serialisation and de-compression can also be embedded in the bit stream, and can be used (e.g., by another computer system) to reconstruct the original circuit in a lossless manner.

A computer-implemented method for generating an identity-based cryptographic key, the method comprising: obtaining a set of private key shares and a set of corresponding public key shares, wherein each private key share is generated based on the personal identifier, and wherein at least one of the set of private key shares is generated by a respective one of a set of key-generating parties; generating an identity-based private key based on each of the one or more private key shares; and generating a partial identity-based public key, wherein the partial identity-based public key is generated based on each of the set of corresponding public key shares; transmitting the partial identity-based public key to at least one of the set of key-generating parties for generating the identity-based public key; and/or generating the identity-based public key, wherein the identity-based public key comprises the personal identifier and the partial identity-based public key.

Systems and computer-implemented methods for freezing or unfreezing digital assets on a blockchain. A freeze administration service may send a signed freeze request to mining nodes, which maintain two blacklists of digital asset identifiers: a pending blacklist and a consensus blacklist. The digital asset identifiers may be transaction outpoints in some cases. If accepted by the mining node, the transaction outpoints in the freeze request are added to the pending blacklist, which causes rejection of any transactions using those outpoints, but does not cause rejection of any new blocks that include transactions using those outpoints. If a consensus threshold of acceptances is reached based on hash power, the request becomes an order and the outpoints are added to the consensus blacklist, which causes rejection of any transaction or block containing a transaction using those outpoints.

The present disclosure proposes methods, devices and systems for synchronising a plurality of event streams using an atomic blockchain transaction, the transaction having multiple inputs, each spending a dust output of a previous transaction for a respective event stream among the plurality, each input having an unspent dust output and a data payload.

The invention relates to distributed ledger technologies such as consensus-based blockchains. A blockchain transaction may include digital resources that are encumbered by a locking script that encodes a set of conditions that must be fulfilled before the encumbered resources may be used (e.g., transferring ownership/control of encumbered resources). A worker (e.g., a computer system) performs one or more computations to generate a proof, which is encoded as part of an unlocking script. A verification algorithm may utilize the proof, a verification key, and additional data such as a cryptographic material associated with the worker (e.g., a digital signature) to verify that digital assets of the transaction should be transferred. As a result of the validation of this transaction, any third party is able to check the contract was executed corrected rather than re-executing the contract, thus saving computational power.

The invention relates to distributed ledge technologies such as consensus-based blockchains. methods for causing an injection of a serialized previous transaction into a locking script 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, with the first transaction including a first script. The first script, as a result of being executed, causes the node to at least obtain a first set of field values corresponding to the first transaction and obtain a second set of field values corresponding to a particular transaction. A second transaction is obtained, with the second transaction having been validated and including a second script. The second script, as a result of being executed, causes the node to at least obtain the first set of field values and the second set of field values of the particular transaction supplied as a result of execution of the first script, extract a transaction identifier from the first set of field values, and determine, based at least in part on the second set of field values, that the particular transaction corresponds to the transaction identifier. The first transaction is validated by executing the first script and the second script.

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.

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.

A computer-implemented method of verifying a link between a first party and a second party, the method being performed by a third party and comprising: obtaining, from the second party, i) a message signed with a first signature based on a first private key of the second party, and ii) a first public key corresponding to the first private key; obtaining, from the second party, iii) the message signed with a second signature based on a second private key of the second party, and iv) a second public key corresponding to the second private key; obtaining, from the first party, v) the message signed with a third signature based on a shared private key known only to the first party and the second party, and a corresponding shared public key; and determining whether the second public key of the second party has been generated based on the first public key of the second party and the shared public key.

A computer-implemented method of encoding a digital contract between a first party of a blockchain network and a second party of the blockchain network, the digital contract being for transferring an amount of a digital asset from the first party to the second party based on a condition of the contract being fulfilled; the method being performed by a trusted third party and comprising: in response to determining that a condition of the contract linked to the second party has been fulfilled, providing the second party with a signature of the trusted third party for inclusion in a transaction of the blockchain, wherein the signature signs a data element representing the fulfilled condition.