An electronic apparatus having a memory arrangement, which is configured to store a plurality of sets of private-key material, and a data processor, which is configured to sign a message in accordance with two or more sets of private-key material from the plurality of sets of private-key material.

Introduced here are computer programs and associated computer-implemented techniques for purchasing, selling, and/or transferring cryptocurrency to be disbursed as a reward for using a specialized payment card. The technology allows cardholders to receive cryptocurrency for completing transactions with specialized payment cards without requiring the card-issuing financial institution directly issue the cryptocurrency.

Aspects of a system and apparatus for accessing online services subject to limitations and restrictions are disclosed. An operator, also referenced herein as a vendor or subscriber, access a third party host server. The operator provides a plurality of data parameters describing a scope and extent of user privileges with respect to one or more services available to the server via a network or internet connection. A user may download an application and use the services, including providing funds through an account funded by the user where applicable. The user's access to the service at issue may be subject to the data parameters at the server, which may provide limitations or restriction on the use of the service by the server, or which, in appropriate cases, may deny service.

Digital or “smart” contracts execute in a blockchain environment. Any entity (whether public or private) may specify a digital contract via a contract identifier in a blockchain. Because there may be many digital contracts offered as virtual services, the contract identifier uniquely identifies a particular digital contract offered by a virtual machine, vendor or supplier. The blockchain is thus not burdened with the programming code that is required to execute the digital contract. The blockchain need only include or specify the contract identifier (and perhaps one or more contractual parameters), thus greatly simplifying the blockchain and reducing its size (in bytes) and processing requirements.

Systems and methods are provided for minting payment loan tokens to conduct digital loan transactions within a blockchain-based digital loan payment network. The payment loan tokens are pegged to fiat currency or digital currency. The computing system is a node in the blockchain-based digital loan payment network. A number of payment loan tokens to be provided to a borrower can be determined based on a digital loan transaction. The borrower is a network participant associated with the blockchain-based digital loan payment network. The number of payment loan tokens can be provided for deposit in a digital wallet associated with the borrower based on the digital loan transaction. Payees that receive payment loan tokens from the borrower can redeem the payment loan tokens as fiat or digital currency. A data record that represents the digital loan transaction can be generated. The data record is posted to a blockchain associated with the blockchain-based digital loan payment network.

A hardware security module (HSM) generates a client key for an account holder of a cryptoasset custodial system. The HSM encrypts the client key to generate an encrypted client key using a hardware-based cryptographic key within a secure storage device. The encrypted client key is transmitted to client devices. The HSM deletes the encrypted client key from the secure storage device. Each client device stores the encrypted client key in an offline secure enclave. A request to authorize a cryptoasset transaction is received. The HSM determines that signed messages endorsing the cryptoasset transaction have been received from at least some client devices in satisfaction of a quorum. The encrypted client key is received from at least one client device. The HSM decrypts the encrypted client key. The HSM signs an approval message for the cryptoasset transaction using a cryptoasset key based at least in part on the client key.

An improved blockchain is described herein in which a user burn transaction can be used to increase the probability that another node is selected as a leader. For example, a node can submit a user burn transaction that references a block commit submitted by another node, and may indicate an amount of cryptocurrency being burned in the user burn transaction. The amount of cryptocurrency being burned in the user burn transaction can be summed with the amount of cryptocurrency burned in the block commit referenced by the user burn transaction to determine the probability that the node that submitted the block commit is selected as a leader. While the node that submitted the user burn transaction cannot be selected as a leader, the node that submitted the user burn transaction can share in a portion of the block reward awarded to the node selected as the leader.

A system enables entities to access a single platform in order to utilize electronic data storage for storing different types of information. One or more computers may operate an electronic data storage processing network that entities can access when updating information in electronic data storage. The electronic data storage processing network may operate a plurality of electronic data storage processing modules, which can include an aggregator module, a formatter module, an operator signer module, and a validator module. Based on the specific use case for which electronic data storage is utilized, recordable data that is to be added to the electronic data storage can be processed by the appropriate aggregating, formatting, signing, and validating functions provided by the electronic data storage processing modules.

Mechanisms for efficiently transferring multiple unspent transaction output (UTXO) tokens in a blockchain network operating a UTXO-based token transaction model are disclosed herein. These methods allow for the use of less computer processing and network bandwidth resources in the transfer of blockchain items, particularly in blockchain schemes with lineage tracking mechanisms (e.g. as may allow for clawback of tokens). Some embodiments comprise generating a delegated account and transferring the UTXO tokens into the delegated account. The ownership of the delegated account can then be transferred to another use of the blockchain network in a single transaction, thereby avoiding the need to individually transfer the UTXO tokens and incur the memory and computational resource burden and costs associated with therewith.

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. The notification address may be associated with an asset or resource represented on the blockchain, or a controller of an asset or resource represented on the blockchain. The notification address may be a network address, a cryptographic key, a uniform resource locator (URI), email address or any other address or identifier which can be represented in the metadata of a transaction script and used as a destination for an electronic communication.