Patent ID: 7716480

Claim:
A network comprising: a plurality of nodes, each of the nodes including a respective transceiver to communicate with other nodes; wherein a transmitting node included in the plurality of nodes generates a plan comprising a plurality of marker states, each marker state comprising a value for a property associated with the transmitting node, wherein the value for a particular point in time is known to an observer node included in the plurality of nodes before that point in time; and wherein when the transmitting node broadcasts information indicative of a given marker state included in the plan, the observer node verifies the value of the property included in the given marker state; wherein each marker state included in the plan is associated with a respective epoch, wherein each epoch comprises a set of time steps; wherein a receiving node included in the plurality of nodes receives information indicative of at least a key chain commitment and a one-way function for the respective epoch associated with the given marker state; wherein, for each time step in the respective epoch associated with the given marker state: during the respective time step: when the transmitting node is to broadcast a data packet, the transmitting node generates a message authentication code for the data packet using a key that is associated with the respective time step and that is from a key chain associated with the key chain commitment, appends the message authentication code to the data packet to create a broadcast packet comprising the data packet and the media authentication code, and broadcasts the broadcast packet; and when the receiving node receives the broadcast packet, the node buffers the broadcast packet; and when the respective time step is over: the transmitting node broadcasts the key included in the key chain that is associated with the respective time step; and when the receiving node receives the key included in the key chain that is associated with the respective time step, the node verifies the received key using the one-way function associated with the respective epoch associated with the given marker state and the key chain commitment for the respective epoch associated with the given marker state and, if the received key is successfully verified, the receiving node uses the received key to authenticate broadcast packets buffered by the receiving node during the respective time step.