Patent ID: 7831998

Claim:
A computer-implemented method for securely modifying a state of one or more communication links by a group of computer systems in a computer network, the group comprising a first computer system and one or more other computer systems, the method comprising: (1) the first computer system randomly selecting one or more first values; (2) the first computer system computing a group value as a first function of the one or more first values; (3) the first computer system performing a network transmission for providing the group value but not the one or more first values to the one or more other computer systems; (4) after the operation (3), the first computer system obtaining a command for changing a state of one or more of the communication links, each communication link being operable to carry network traffic in the computer network, each state defining one or more restrictions or an absence of the one or more restrictions in communicating over the computer link; (5) in response to the command, the first computer system performing a network transmission to the one or more other computer systems for providing an indication to change the state of the one or more of the communication links, the indication comprising authentication data to authenticate the indication to the one or more other computer systems, the authentication data comprising one or more second values which are either (i) one or more first values, or (ii) intermediate values obtained in computing the group value in the operation (2), or (iii) a combination of one or more of the first values and one or more of the intermediate values; wherein the authentication is to be performed by the one or more other computer systems without computing at least one second value from the group value; wherein the operation (5) comprises the first computer system determining whether the command is for performing a first type of change of the state of the one or more communication links or a second type of change of the state of the one or more communication links; wherein the one or more second values depend on whether the command is for performing the first type of change or the second type of change.