Fun with message...

message.erl

-module(message).

-export([decode/3, decode/4, encode/1]).

decode(M1, M2, M3) ->
  decode(M1, M2, M3, float_to_integer(length(M1)/8 - 1)).

decode(M1, M2, M3, Size) ->
  [L1, L2, L3] = [[list_to_integer(string:substr(M, I*8+1, 8), 2) || I <- lists:seq(0, Size)] || M <- [M1, M2, M3]],
  [A bxor B bxor C || {A, B, C} <- lists:zip3(L1, L2, L3)].

encode(Message) ->
  encode(Message, "", "", "").

encode([], Acc1, Acc2, Acc3) ->
  io:format("~p~n~p~n~p~n", [Acc1, Acc2, Acc3]),
  decode(Acc1, Acc2, Acc3, float_to_integer(length(Acc1)/8 - 1));
encode([L|Rest], Acc1, Acc2, Acc3) ->
  {A, B, C} = reverse(L),
  encode(Rest, Acc1 ++ A, Acc2 ++ B, Acc3 ++ C).

reverse(N) ->
  A = float_to_integer(N/2),
  M = N bxor A,
  B = float_to_integer(M/2),
  C = M bxor B,
  N = A bxor B bxor C,
  {string:right(integer_to_list(A, 2), 8, $0),
   string:right(integer_to_list(B, 2), 8, $0),
   string:right(integer_to_list(C, 2), 8, $0)}.

float_to_integer(N) ->
  list_to_integer(float_to_list(N, [{decimals,0}])).