Very curious definitions, as I have been taught that “negative freedom” is a freedom that the government merely has to abstain from infringing, like protection of property, and that “positive freedom” is something that actually requires the government to take some positive action to ensure, like your freedom to life requires that you have the minimum sustenance.
Or, per Wikipedia: “Negative liberty is freedom from interference by other people. Negative liberty is primarily concerned with freedom from external restraint and contrasts with positive liberty (the possession of the power and resources to fulfill one’s own potential).”
Your definition seems like it was concocted to undo the negative freedom as it has hitherto been.
Secrecy of correspondence being one of the said negative freedoms.