Key distribution patterns using tangent circle structures

The problem of key management in a communications network is of primary importance. A key distribution pattern is an incidence structure which provides a secure method of distributing keys in a large network reducing storage requirements. It is of interest to find explicit constructions for key distribution patterns. In some paper of C. O'Keefe, examples are shown using the finite circle geometries (Minkowski, Laguerre and inversive planes); in a paper of K. Quinn examples are constructed from conics in finite projective and affine planes. In this paper, we construct some examples using the finite tangent-circle structures, introduced in a paper of Quattrocchi and Rinaldi (1988) and we give a comparison of the storage requirements.