A Generalised Formula for Calculating the Resilience of Random Key Predistribution Schemes
A commonly used metric for comparing the resilience of key pre-distribution schemes is fails, which measures the proportion of network connections which are 'broken' by an adversary which has compromised s nodes. In 'Random key pre-distribution schemes for sensor networks', Chan, Perrig and Song present a formula for measuring the resilience in a class of random key pre-distribution schemes called q-composite schemes. The authors present a correction to this formula for schemes where more than one key may be used to secure a link between a pair of nodes. Their corrected formula features an additional parameter which makes it applicable to a wider variety of random key pre-distribution schemes, including the original Eschenauer Gligor scheme.