Patent attributes
The technology described in this document can be embodied in a method that includes receiving, at one or more servers from a first computing device, (i) authentication information identifying a user-account associated with (a) the first computing device or (b) an application executing on the first computing device, and (ii) a transaction identifier generated by a second computing device. The transaction identifier is obtained by the first computing device by detecting one or more parameters of a magnetic field generated by the second computing device. The method also includes determining, by the one or more servers, that the user-account is authorized to initiate a transaction identified by the transaction identifier, and in response to determining that the user-account is authorized to initiate the transaction, transmitting, from the one or more servers to the second computing device, confirmation information usable by the second computing device to proceed with the transaction.