Question about md_open() and random

Victor Stinner haypo at inl.fr
Thu Jul 13 10:32:39 CEST 2006


> On Mon, 10 Jul 2006 14:38, haypo at inl.fr said:
>
>> Yep, exactly! And you didn't anwer to my question: which hash algorithm
may use random? Hash functions are determinitic, isn't it?
>
> It is not that the hash algorithm are using random but hashing is a very
common operation and often used right before other operations require
random.  Thus doing a fast random collect there is a Good Thing.

I read _gcry_fast_random_poll() source code an finally understood :-p

This function calls do_fast_random_poll() which feed random pool with
current time, getrusage(), etc.

So : ok, it's a very good idea :-)

> If you can provide profile data showing that it is really a problem for
your application we can add a control call to explicitly disable these
automatic polls.

It was more a question than a performance problem.

Haypo






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