Patent ID: 8397062

Claim:
A central node for issuing certificates to a plurality of nodes associated with the central node in a network, the central node comprising: a receiver that is configured to receive a first key from at least one node from among the plurality of nodes; a processor which is configured to generate a second key based on the received first key and generate a certificate for the at least one node; and a transmitter that is configured to transmit the generated certificate to the at least one node, wherein: the first key is a key from a first authentication key chain comprising a plurality of keys generated by the at least one node for use in authenticating messages transmitted by the at least one node, the at least one node configured to generate a third authentication key chain comprising a plurality of keys and further configured to authenticate messages using at least two message authentication codes that are computed using a unique key from each of the first authentication key chain and the third authentication key chain, and the certificate generated by the processor includes the second key and an identity of the at least one node.