[erlang-questions] Password generator in Erlang

Kenji Rikitake <>
Tue Aug 21 13:25:33 CEST 2012


Samuel is right. SFMT is NOT cryptographically safe.

Kenji Rikitake

On Fri, Aug 17, 2012 at 7:53 PM, Samuel <> wrote:
>> We also moved to "Tiny Mersenne Twister"
>> (https://github.com/jj1bdx/tinymt-erlang) instead of using
>> the standard random:uniform since the last Yaws security alert
>> (http://erlang.org/pipermail/erlang-questions/2012-June/067626.html).
>> Is this sufficient or should we also find a way to generate a unpredicatble
>> seed for it?
>
> As said, I am not a security expert, but as far as I can read, the
> goals of that algorithm are to keep a small state with good
> statistical properties, it says nothing about security (which doesn't
> necessarily mean it is insecure, of course). A PRG can have good
> statistical properties and still be insecure, being a secure PRG is a
> stronger assumption. That is why erlang:random is fine for non
> cryptographic uses, but for security you need something more complex.
>
> Anyway, you always need a seed no one can guess. Same seed, same
> sequence, so if someone guesses your seed it basically gets all your
> passwords in return.
>
> Regards
> --
> Samuel



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