  In the context of ambient networks where each small device must trust its
neighborhood rather than a fixed network, we propose in this paper a
\textit{trust management framework} inspired by known social patterns and based
on the following statements: each mobile constructs itself a local level of
trust what means that it does not accept recommendation by other peers, and the
only relevant parameter, beyond some special cases discussed later, to evaluate
the level of trust is the number of common trusted mobiles. These trusted
mobiles are considered as entries in a local database called history for each
device and we use identity-based cryptography to ensure strong security:
history must be a non-tansferable object.
