Patent ID: 8799247

Claim:
A method for ascertaining consistency of a transaction in a untrusted database, comprising: providing a server computer in communication with a computer network including a client computer, wherein the server computer hosts the untrusted database as provided by an owner of the untrusted database through an owner computer; generating by the server computer before-transaction authentication data corresponding to an initial state of the untrusted database; sending from the client computer a transaction including a transaction sequence number; receiving by the server computer the transaction including the transaction sequence number; confirming by the server the transaction sequence number is greater than any previously received transaction sequence number; executing by the server computer the transaction on the untrusted database to obtain an executed transaction; generating by the server computer an update based on the executed transaction; applying by the server computer the update to the untrusted database; creating by the server computer after-transaction authentication data corresponding to a subsequent state of the untrusted database, wherein the subsequent state is resultant from the update based on the executed transaction; transmitting a report message from the server computer to the client computer, wherein the report message comprises the before-transaction authentication data and the after-transaction authentication data; and verifying by the client computer faithful execution of the untrusted database by the server computer using the report message.