anchor.diff:  -export([rand_seed/1]).
   
   %% Old interface. Now implemented with the New interface
  +-export([hmac/3, hmac/4, hmac_init/2, hmac_update/2, hmac_final/1, hmac_final_n/2]).
  +-export([cmac/3, cmac/4]).
  +-export([poly1305/2]).
   -export([stream_init/2, stream_init/3,
            stream_encrypt/2,
            stream_decrypt/2,
  
positive.code: mac_update_nif(_Ref, _Data) -> ?nif_stub.
  mac_final_nif(_Ref) -> ?nif_stub.
  
  
  %%%---- HMAC
  
  
negative.code: mac_final(Ref, MacLength) ->
      erlang:binary_part(mac_final(Ref), 0, MacLength).
  
  
  %%%----------------------------------------------------------------
  %%% NIFs for the functions above
  
  mac_nif(_Type, _SubType, _Key, _Data) -> ?nif_stub.
  
  