The present disclosure relates to a method for secure, traceable and privacy-preserving with anonymity revocation digital currency transfer to at least a first user from a second user among a plurality of banked and unbanked users by using a distributed ledger comprising a plurality of ledger nodes, wherein said users perform Digital Currency transfers by adding transactions on this ledger using user devices configured to be connected to said nodes, to a registration authority and to a revocation authority, said authorities owning each one a public/private key pair, comprising: an enrollment phase, performed by a user device of said first user, comprising: sending to the registration authority evidence of the first user's identity, generating a first user identification key pair comprising a first user identification public key and a first user identification secret key, sending to the registration authority said generated first user identification public key, receiving from the registration authority a signed token generated by the registration authority after the registration authority verified first user's identity based on said evidence, said signed token being generated by signing with the registration authority secret key a token comprising said first user identification public key and said first user's identity encrypted with said revocation authority public key, a transaction phase, performed by said user device of said first user, comprising: participating with said second users in a Digital Currency transfer transaction to be added to the distributed ledger, wherein said signed token enables the revocation authority to revoke first user's anonymity by retrieving first user's identity.

Various examples relate to apparatuses, devices, methods and computer programs for a group leader and a group member of a group of nodes of a blockchain network. The apparatus for the group leader comprises interface circuitry, machine-readable instructions, and processor circuitry to execute the machine-readable instructions to manage a membership of nodes of the blockchain network in the group of nodes, perform or delegate blockchain-related computational activity on behalf of the group of nodes according to an energy criterion.

A Bluetooth financial card, belonging to the field of information security, and comprising a receiving module, an acquisition module, a first execution module, a selection module, a cardholder verification module, a second execution module, an online transaction message organization sending module, an authorization response receiving module, and a transaction confirmation message organization sending module. The technical solution disclosed in the present invention overcomes the defects that the existing contact-type financial cards and contactless-type financial cards are inconvenient to operate in a transaction process, improving the working efficiency, and also saving on the manufacturing cost. The Bluetooth financial card communicates with an upper computer via Bluetooth, which makes the transaction operation more convenient; and when using a fingerprint verification type of cardholder verification method, the transaction is more convenient and secure.

A cryptographic method of performing a tokenised transaction between a payment offering party and a payment accepting party is described. The tokenised transaction is mediated by a transaction scheme. The payment accepting party is provided with a merchant identity and a merchant certificate associated with that identity by the transaction scheme provider. The payment accepting party provides the merchant identity and transaction seed data to the payment offering party. The payment offering party validates the merchant identity and uses the merchant identity and the transaction seed data to generate a cryptogram for the tokenised transaction. The payment offering party provides the cryptogram to the payment accepting party for transmission to the transaction scheme provider for authorisation of the tokenised transaction. A suitable user computing device and merchant computing device for acting as payment offering party and payment accepting party respectively are also described.

Methods and systems for a browser extension system are disclosed. In some embodiments, a browser extension server includes a communication device configured to communicate with a first computing device executing a browser extension application and a web browser application and a second computing device executing an authentication application. The browser extension server further includes a memory storing instructions, and a processor configured to execute the instructions to perform operations. The operations may include receiving from the first computing device an indication of a financial service account associated with the first computing device, detecting a payment field in a web page provided by the computing device through the web browser application and, in response, generating a secure token mapped to the financial service account. The operations may further include sending the second computing device an authentication request, receiving an authentication response, and populating the payment field with the secure token.

A method for posting of auditable, immutable data to a blockchain includes: receiving a blockchain comprised of a plurality of blocks, each block being comprised of 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.

The described implementations enable a seller to sell items through multiple e-commerce channels without having to maintain independent merchant accounts at each channel. For example, a seller may sell items directly and through a management service. When a user request to purchase an item from the seller through the management service is received, the management service sends the purchase information to the seller so that the seller can complete the purchase as if the purchase were being made directly with the seller. Upon completion of the purchase, the seller provides a confirmation back to the management service and provides the item directly to the user.

Disclosed is a method, a device, and/or a system of rapid and secure off-ledger cryptocurrency transactions through cryptographic binding of a private key to a possession token. In one embodiment, a method for rapid and secure ledger-less transfer of a quantity of cryptocurrency includes generating a public-private key pair, securely storing the private key and utilizing the public key as a public address. The method verifies a ledger transaction on a distributed ledger network associated the quantity of cryptocurrency with the public address. The method generates a possession token having a state indicated by a state indicator. The state evolves upon transfer between two computing devices. The method cryptographically associates the ledger token and the possession token through incorporation of the public address into data generating the state indicator. The possession token is transferred to a computing device over the network while retaining the private key in secure custody.

Various embodiments are generally directed to NFC-based mobile currency transfers. A mobile payment may be programmatically initialized when at least two mobile devices come into NFC communications range. A payment card associated with an account used to fund the currency transfer may be tapped to one or more of the devices to allow a server to validate the currency transfer.

Systems, methods and computer program code are provided for receiving a token and a request to generate a sub-token based on the token, identifying an association between the token and a primary account number (PAN) of a user, generating a sub-token associated with the token and the PAN, and providing the sub-token for use in a payment transaction.