anchor.diff:  mac('hmac-sha2-512', Key, SeqNum, Data) ->
   	crypto:hmac(sha512, Key, [<<?UINT32(SeqNum)>>, Data]).
   
  +
  +%%%----------------------------------------------------------------
   %% return N hash bytes (HASH)
   hash(_SSH, _Char, 0) ->
       <<>>;
  
positive.code:     Kj = crypto:hash(HashAlg, [K, H, Ki]),
      hash(K, H, <<Ki/binary, Kj/binary>>, N-128, HashAlg).
  
  
  kex_h(SSH, Key, E, F, K) ->
      KeyBin = public_key:ssh_encode(Key, ssh2_pubkey),
      L = <<?Estring(SSH#ssh.c_version), ?Estring(SSH#ssh.s_version),
  
negative.code: 	    yes == yes_no(Ssh, "New host " ++ PeerName ++ " accept")
      end.
  
  known_host_key(#ssh{opts = Opts, key_cb = Mod, peer = {PeerName,_}} = Ssh, 
  	       Public, Alg) ->
      case Mod:is_host_key(Public, PeerName, Alg, Opts) of
  	true ->
  	    ok;
  