A cryptographic scheme associated with a transaction service is received at a first computer system. Subsequent to receiving the cryptographic schema, the first computer system performs a configuration process for a transaction to be performed with the transaction service. The configuration process includes receiving a request for transaction configuration information from a client device. The request includes a cryptographic token generated by a second computer system the transaction service. The first computer system determines whether to grant the request based on analyzing the cryptographic token according to the cryptographic schema. Based on the determining, the first computer system sends transaction configuration information. The configuration process is performed by first computer system independent of communication between the second computer system and the first computer system.

A method for preventing unauthorized repeat purchases of a product includes: storing a plurality of purchase data values, each related to a completed financial transaction and including a purchase identifier; receiving an authorization request for a new financial transaction from an external system, the authorization request including a specific identifier; identifying a number of purchase data values where the included purchase identifier matches the specific identifier; and transmitting an authorization response to the external system, the authorization response including (i) an approval of the new financial transaction if the number of purchase data values is below a predetermined number, or (ii) a denial of the new financial transaction if the number of purchase data values is equal to or above the predetermined number.

A method including receiving, by a server computer, a request message from a token requestor computer on behalf of a user device. The request message comprising a first current token tracking value and a first function index value. The server computer can determine a second function index value. The server computer can then compare the first function index value to the second function index value. If the first function index value and the second function index value match, the server computer can determine a function based on the first function index value and a stored function table associated with the user device. The server computer can then determine a second current token tracking value based on the function, then compare the first current token tracking value to the second current token tracking value. The server computer can generate a response message in response to the comparing.

A method for authenticating e-commerce transactions involves receiving, from a payment network computer, a first authentication request message to authenticate a transaction associated with a payment account, the first authentication request message being initiated by an issuer domain computer not implementing a 3-D Secure authorization protocol, determining that the issuer domain computer has configured, at the access control server computer, a decision function of a second portion of the 3-D Secure authorization protocol and in response thereto, transmitting, to the issuer domain computer, a decision request message and information associated with the transaction, the decision request message requesting the issuer domain computer to determine an action for authenticating the transaction based on the information associated with the transaction and one or more programmatic rules of the issuer domain computer, the transmitting occurring in lieu of the access control server computer executing the decision function at the access control server computer.

A time-dependent blockchain based self-verification user authentication method of the present disclosure includes, a reservation registration step for registering reservation time which is obtained by adding a set time to an input time, and an authentication subject to a blockchain which is distributed and stored in a plurality of nodes; a reservation notification step for notifying a notification group, which is associated with the authentication subject, of a reservation registered in the reservation registration step; a verification step for verifying authentication request time and the reservation time, which has been registered to the blockchain, when there is an authentication request with respect to the authentication subject; and a step for granting authentication when the authentication request time is within a valid range of the reservation time in the verification step.

Disclosed are non-limiting methods for authenticating devices, including receiving a request for a device authentication identifier, transmitting a device authentication request message via a frame embedded in a webpage of a merchant website, the device authentication request message including challenge data associated with a challenge, receiving a device authentication response message via the frame embedded in the webpage of the merchant website based on the device authentication request message, the device authentication response message including challenge response data associated with a challenge response, transmitting the device authentication identifier message based on the device authentication response message, receiving a transaction request message for a transaction, including the device authentication identifier and transaction data associated with the transaction, determining the device score based on the device authentication identifier, and generating an authorization request message based on the transaction data and the device score. Systems and computer program products are also disclosed.

A computer-implemented method for improving security of smart contract comprises: obtaining a first and a second transactions both invoking a smart contract, wherein the first transaction is associated with a protection condition; executing the second transaction and updating a current state of the smart contract; determining whether the updated current state of the smart contract satisfies the protection condition; in response to determining that the updated current state satisfies the protection condition, executing the first transaction, and recording the second and the first transactions into a data block for adding to a blockchain; and in response to determining that the updated current state does not satisfy the protection condition, recording the second transaction into another data block for adding to the blockchain, without executing the first transaction.

A system and method for transacting cryptographic currency is described. An exchange database associated with a number of buyers and sellers is maintained at a host computer system. Cryptographic currency is received from one or more of the sellers at an exchange wallet associated with the exchange database. A match is created within the exchange database, including a buy offer for the cryptographic currency from a buyer and a sell offer for the cryptographic currency from a seller. A cryptographic currency withdrawal request is received from the buyer, and in response, the host computer system determines that a total amount of cryptographic currency represented in the exchange database matches a total amount of the cryptographic currency within the exchange wallet, transfers the cryptographic currency to the buyer's wallet, and updates the exchange database by deducting a first value of the cryptographic currency that is transferred to the buyer's wallet.

Systems and methods described herein include an application comprising instructions for execution on first and second devices including one or more processors and memory, the application being configured to purchase one or more certificates by a first process via one or more blockchain transactions. The application may redeem the one or more certificates received by a second process via one or more blockchain transactions. The second device may exchange one or more codes to designate the one or more certificates as used on the first device. The system may include one or more servers in communication with the application, and may generate a message containing updated redemption information of the one or more certificates when the updated redemption information has been stored in one or more databases, retrieve data from a plurality of data sources, and generate one or more smart contracts based on the retrieved data.

Systems and methods for the deployment of cloud-based systems using a distributed ledger are disclosed. The system may include a cloud provider system and a distributed ledger. The cloud provider system may be configured to deploy cloud-based systems and APIs to enable one or more participant systems to leverage cloud-based resources. The distributed ledger may record events, functionalities, and operations from the cloud provider system, the participant systems, and the deployed cloud-based systems and APIs.