The essential security function that warders have of keeping control o
ver the penal population takes into account a certain know-how informa
l exchange system with prisoners which is non-stated and which deviate
s from the formal missions, rules and regulations, official means whic
h have been entirely defined beyond the prison walls. The warders are
working within a tight margin and due to the increasing contradictions
between internal and external security, improvement of living conditi
ons in the prison and internal security, between security and reinsert
ion, between prisoners' rights and keeping order, this margin is becom
ing even tighter. This dualism points out the reality of the situation
at a time when the management of prisons and their external social tr
eatment has also reached a division.