1. A method comprising: transmitting, by a controller comprising at least one processor, a first permission certificate and an indication of at least one condition of a contract to a verification authority; receiving, by the controller, the first permission certificate, in which the received first permission certificate is signed by a third party, and in which the received signed first permission certificate verifies that the at least one condition of the contract has been satisfied; and after receiving the signed first permission certificate, transmitting, by the controller, a second permission certificate to a seller, the second permission certificate indicating permission is granted by a trusted agent for the seller to acquire an amount of funds.