Non-Arbitrary Keys of Fault-Tolerance Signatures

Inhalt:
Fault-tolerance signatures authenticate the original sender of a routed message as well as the cosigning nodes along the message path – with the purpose to detect technical errors rather than human attacks, in contrast to general digital signatures. In this paper an existing scheme for fault-tolerance signatures is (trivially) extended for fault-tolerance cosignatures. The main contribution, however, is the new idea that fault-tolerance signature keys need not be chosen arbitrarily (to prevent “guessing” them by a faulty unit). Instead the keys are calculated according to an algorithm that guarantees perfect detection of specific errors, whereas arbitrary key selection only achieves detection with high probability. In this paper the errors with guaranteed detection are identified theoretically. An extensive simulation confirms the conclusions and, moreover, shows 100% coverage of additional errors – depending on heuristic properties of the algorithm.