With regard to the Estonian model, where there are silos—depending on the different authority concerned, of education, health, taxes or whatever—the individual chip used to access one's personal information or that can be requested from the individual is siloed. However, you raised concerns about the movement of information between silos and the possible points of penetration through either a deliberate or an accidental process in the creation.
On February 5th, 2019. See this statement in context.