Signature Amortization Using Multiple Connected Chains

Amortization schemes for authenticating streamed data have been introduced as a solution to reduce the high overhead that sign-each schemes suffer from. The hash chains structure of amortization schemes and the number of hash values appended to other packets affect the efficiency of the authentication scheme specially against packet loss. Which packets should have hashes appended to the signature packet and how many hashes to append to it have no solutions yet. This paper introduces a new hash chain construction to achieve longer resistance against packet loss and reduces the overhead. The proposed scheme consists of multiple connected chains, each chain links several packets together. Our scheme specifies clearly how to choose the packets that should have hashes appended to a signature packet, in addition to deriving their loss probability. We study the effect of the number of hashes that are appended to a signature packet on the overhead. We introduce a measure so as to know the number of packets receivers need to buffer until they can authenticate the received packets. The number of chains of our model plays a main role in the efficiency of our scheme in terms of loss resistance and overhead.