The present disclosure relates to a system for locking a digital asset. In one implementation, the system may include a first computer node that reads a private data store associated with the first computer node and/or reads a distributed ledger to confirm a digital asset is unlocked and can be transferred from the first computer node. The first computer node cryptographically signs and sends a proposed digital lock to a second computer node. When activated, the digital lock prevents transfer of the digital asset from the first computer node to another computer node that is not the second computer node. The first computer node also reads a distributed ledger to confirm the distributed ledger contains the digital lock in an activated state. The first computer node transfers the digital asset from the first computer node to the second computer node.

A computer-implemented method for performing by a node of a network of nodes for maintaining at least part of a distributed ledger maintained by the network of nodes is described. The method comprises maintaining at least part of the distributed ledger. The at least part of the distributed ledger is configured to store records and associated verification data for the records. The verification data for a record identifies: (i) a sequence of nodes in the network which received the intended record during a verification procedure; and (ii) the respective event state assigned by each node of the sequence of nodes to the intended record during the verification procedure.

A method of executing a transaction of a blockchain. The transaction comprises at least one output comprising a locking script, and the locking script comprises an instance of a first opcode and one or more instances of a second opcode. Each instance of the second opcode separates portions of the locking script. Upon calling the instance of the first opcode, a first data element is read from at least one stack, the first data element being generated during execution of the locking script with an unlocking script of a different transaction. A first part of the locking script that follows an instance of the second opcode corresponding to the first data element is output.

A method for posting of auditable, immutable data to a blockchain includes: receiving a blockchain including a plurality of blocks, each block including at least a block header and one or more transaction values, wherein each transaction value includes at least a transaction hash; receiving a data file associated with a specific transaction hash included in a block in the blockchain, wherein the data file includes one or more variables; modifying at least one of the one or more variables included in the data file; generating a new hash value via application of one or more hashing algorithms to the modified data file; generating a new transaction value based on at least the generated new hash value and the specific transaction hash; digitally signing the generated new transaction value; and electronically transmitting the signed new transaction value.

There is provided a method and system for selection of response message(s), comprising: receiving from an initiator client terminal a function message including an unencrypted target value and a public key, receiving respective response messages to the function message from responding client terminals, each respective response comprising an unencrypted partial value of the target value and a parameter encrypted with the pubic key, receiving, from the initiator client terminal, a selection of response message(s) according to a ranking of the encrypted parameters, wherein a sum of the unencrypted partial values of the selected response message(s) is according to a requirement of the target value, and receiving a validation for the selected response message(s) from corresponding responding client terminals, wherein each of the corresponding responding client terminals is provided with all partial values and all unencrypted parameters associated with all of the selected response message(s).

The present invention relates to a method and a system for inscribing and securely storing cryptographic keys on a physical medium, and to a corresponding physical medium, comprising the following steps: from a first management entity (31), generating (1) a first pair of asymmetric cryptographic keys comprising a first user public key (pub1) and a first user private key (priv1), inscribing (2) the first user private key (priv1) onto a physical medium, and affixing (4) a first tamper-evident concealing element (hol1) to the physical medium in order to conceal the first user private key (priv1) and seal same, said first user private key (priv1) being accessible only by visibly breaking said first tamper-evident concealing element (hol1); from the second management entity (32), generating (6) a second pair of asymmetric cryptographic keys comprising a second user public key (pub2) and a second user private key (priv2), inscribing (7) the second user private key (priv2) onto the physical medium and affixing (9) a second tamper-evident concealing element (hol2) to the physical medium in order to conceal the second user private key (priv2) and seal same, said second user private key (priv2) being accessible only by visibly breaking said second tamper-evident concealing element (hol2); generating (10) at least one last user public key (pub0) and/or at least one cryptographic address (adr, adr-mult) from the first user public key (pub1) and the second user public key (pub2), inscribing (11) said at least one last public user key (pub0) and/or said at least one cryptographic address (adr, adr-mult) onto the physical medium, and verifying (12, 13) same, and finally recovering the private keys (priv1, priv2) comprising the generation of a last user private key (priv0) corresponding to the last user public key (pub0) and/or to said at least one cryptographic address (adr, adr-mult).

Techniques are described for generating semi-random private transaction identifiers for users that are meaningful to data providers and can be used by data providers to perform internal queries for user data. A user provides input to an identity management service indicating the user's consent to link their user account at the identity management service to one or more data providers. The identity management service stores a group blinded transaction identifier (GBTI) based on transaction identifiers generated by one or more data providers. When the user desires to obtain a service from a service provider, the user obtains GBTI-derived value from the identity management service and sends it to the service provider. The service provider sends the GBTI-derived value (and possibly other information) to the data provider to prove that it has the user's consent to obtain desired data or insights about the user but without infringing the user's privacy.

Methods and systems for the use of multi-party computation (“MPC”) key systems that involve the use of multiple parties, each of which hold respective private data that may be used to evaluate a computation without ever revealing any of the private data held by each party to perform blockchain operations. Using the MPC key systems, the methods and systems generate secure, encrypted communications across distributed computer networks for authorizing use of cryptography-based digital repositories in order to perform blockchain operations in decentralized applications.

Embodiments include methods and systems for linking high-value tokens using a low-value token, comprising receiving, from an electronic data server, a first high-value token and a request for a low-value token, the first high-value token being associated with sensitive data associated with a user, and the low-value token being associated with a subset of the sensitive data associated with the user. The methods and systems further comprise providing the low-value token to the electronic data server, and receiving, from a second electronic data server, the low-value token and a request for a second high-value token, the low-value token having been provided to the second electronic data server by the electronic data server. The methods and systems further comprise generating a second high-value token associated with the sensitive data associated with the user, and providing the second high-value token to the second electronic data server.

Systems and methods are disclosed for automating digital asset transfers based on historical transactions. In one implementation, a notification corresponding to a first transaction or operation associated with a first entity is received. Based on the notification, a second transaction or operation is initiated with respect to one or more digital tokens. One or more digital tokens are received in response to the second transaction. At least one of the one or more digital tokens, as secured via one or more cryptographic keys, is stored in a wallet associated with the first entity.