Consensus with written messages under link faults

This paper shows that deterministic consensus with written messages is possible in presence of link faults and compromised signatures. Relying upon a suitable perception-based hybrid fault model that provides different categories for both node and link faults, we prove that the authenticated Byzantine agreement algorithms OMHA and ZA of Gong, Lincoln and Rushby (1995) can be made resilient to f/sub l/ link faults per node by adding 3f/sub l/ and 2f/sub l/ nodes, respectively. Both algorithms can also cope with compromised signatures if the affected nodes are considered as arbitrary faulty. Authenticated algorithms for consensus are therefore reasonably applicable even in wireless systems, where link faults and intrusions are the dominating source of errors.