18 U.S.C. § 1704 : US Code - Section 1704: Keys or locks stolen or reproduced

      Whoever steals, purloins, embezzles, or obtains by false pretense
    any key suited to any lock adopted by the Post Office Department or
    the Postal Service and in use on any of the mails or bags thereof,
    or any key to any lock box, lock drawer, or other authorized
    receptacle for the deposit or delivery of mail matter; or
      Whoever knowingly and unlawfully makes, forges, or counterfeits
    any such key, or possesses any such mail lock or key with the
    intent unlawfully or improperly to use, sell, or otherwise dispose
    of the same, or to cause the same to be unlawfully or improperly
    used, sold, or otherwise disposed of; or
      Whoever, being engaged as a contractor or otherwise in the
    manufacture of any such mail lock or key, delivers any finished or
    unfinished lock or the interior part thereof, or key, used or
    designed for use by the department, to any person not duly
    authorized under the hand of the Postmaster General and the seal of
    the Post Office Department or the Postal Service, to receive the
    same, unless the person receiving it is the contractor for
    furnishing the same or engaged in the manufacture thereof in the
    manner authorized by the contract, or the agent of such
    manufacturer - 
      Shall be fined under this title or imprisoned not more than ten
    years, or both.