anchor.diff:       {ppspp_content_integrity_check_method,ppspp_merkle_hash_tree},
        {ppspp_merkle_hash_function,ppspp_sha1},
        {ppspp_minimum_version,1},
  -     {ppspp_swarm_id, chairman_miaow_hash()},
  +     {ppspp_swarm_id, m74_hash()},
        {ppspp_version,1}].
   
   %% UDP wire format as passed to handle_packet_sync from gen_udp socket
  
positive.code: %% when the standard is specified. e.g.;
  %%  endpoint today contains "127.0.0.1:52021"
  %% but in future could equally be;
  %%  udp://ppspp.peer.org:7777?channel=12345,name=chairman_miaow.png
  %%  udp://ppspp.peer.org:7777?channel=12345,hash=66a10862baeebdff8462e745a2de18cf9ce11ae5
  %% beam://swirl_7777?hash=66a10862baeebdff8462e745a2de18cf9ce11ae5
  %% The beam transport uses the Erlang VM's clustering services, and
  %% assumes the existence of a registered service `swirl_7777` somewhere.
  transport() -> orddict:from_list([{peer,{127,0,0,1}},
  
negative.code: initiator_channel() -> << 16#77777777:32/big>>. %% initiator peer channel
  responder_channel() -> << 16#88888888:32/big>>. %% responder peer channel
  
  m74_hash() -> convert:hex_string_to_padded_binary("c89800bfc82ed01ed6e3bfd5408c51274491f7d4").
  
  handshake_options(packed) ->
      M74_hash = m74_hash(),
      <<  ?PPSPP_VERSION,                     1, %% ppspp version
          ?PPSPP_MINIMUM_VERSION,             1, %% ppspp max version
          ?PPSPP_SWARM_ID_LENGTH,      20:?WORD, %% swarm id length (160 bits)
          M74_hash/binary                      , %% the merkle hash requested
          ?PPSPP_INTEGRITY_CHECK_METHOD,      1, %% optional integrity check method
          ?PPSPP_MERKLE_HASH_FUNCTION,        0, %% merkle please
          ?PPSPP_CHUNK_ADDRESSING_METHOD,     2, %% chunk addressing method 2
  