  In this article we provide a formal framework for reidentification in
general. We define n-confusion as a concept for modelling the anonymity of a
database table and we prove that n-confusion is a generalization of k-
anonymity. After a short survey on the different available definitions of k-
anonymity for graphs we provide a new definition for k-anonymous graph, which
we consider to be the correct definition. We provide a description of the
k-anonymous graphs, both for the regular and the non-regular case. We also
introduce the more flexible concept of (k,l)-anonymous graph. Our definition of
(k,l)-anonymous graph is meant to replace a previous definition of (k,
l)-anonymous graph, which we here prove to have severe weaknesses. Finally we
provide a set of algorithms for k-anonymization of graphs.
