  In the scenario of the Voice Privacy challenge, anonymization is achieved by
converting all utterances from a source speaker to match the same target
identity; this identity being randomly selected. In this context, an attacker
with maximum knowledge about the anonymization system can not infer the target
identity. This article proposed to constrain the target selection to a specific
identity, i.e., removing the random selection of identity, to evaluate the
extreme threat under a whitebox assessment (the attacker has complete knowledge
about the system). Targeting a unique identity also allows us to investigate
whether some target's identities are better than others to anonymize a given
speaker.
