The present disclosure relates to a bipolar junction transistor structure that significantly reduces current crowding while improving the current gain relative to conventional BJTs. Such techniques may provide for negotiation of an encryption mechanism as part of the setup for connectionless transmissions and subsequent secure connectionless uplink transmissions. Between the first wall and the second wall, a first rib parallel with the bottom portion for connecting the first wall and second wall is installed. Each projection has a slit into which one of end portions of the partition plates are inserted.