[erlang-questions] Password generator in Erlang

Sverker Eriksson <>
Tue Aug 14 17:43:24 CEST 2012


Try only call random:seed(A1, A2, A3) once at start.

For cryptographic safe random generation look at crypto module.

/Sverker


Zabrane Mickael wrote:
> Hi guys,
>
> This one fires a lot of collisions 
> (http://schemecookbook.org/Erlang/NumberRandomNumber):
>
> ------------------
> test() ->
>     crypto:start(),
>     N = 10000,
>     io:format("Generate ~p random passwords and check for collisions ...~n", [N]),
>     test(N, dict:new(), 0).
> test(0, _, C) ->
>     io:format("Number of collisions: ~p~n", [C]);
> test(N, Dict, C) ->
>     Password = passwd(),
>     case dict:find(Password, Dict) of
>         {ok, _} -> %% collision detected
>             test(N - 1, Dict, C + 1);  
>         error ->
>             test(N - 1, dict:append(Password, 1, Dict), C)
>     end.
>
> passwd() ->
>     passwd(8).
> passwd(Length) ->
>     {A1,A2,A3} = now(),
>     random:seed(A1, A2, A3),
>     lists:flatten(lists:foldl(fun(_,AccIn) ->
>                                       [random:uniform(90) + 32 | AccIn] end,
>                               [], lists:seq(1,Length))).
>
> ----------------
>
>  > passwd:test().
> Generate 10000 random password and check for collisions ...
> Number of collisions: 1182
>
> Anything better guys? Something with less collisions if possible.
>
> Regards,
> Zabrane
>
>   




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