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From: "Ard Biesheuvel" <ard.biesheuvel@linaro.org>
To: Paul Dale <paul.dale@oracle.com>
Cc: Laszlo Ersek <lersek@redhat.com>,
	Jian J Wang <jian.j.wang@intel.com>,
	 edk2-devel-groups-io <devel@edk2.groups.io>,
	"Lu, XiaoyuX" <xiaoyux.lu@intel.com>
Subject: Re: why does RAND_add() take "randomness" as a "double"?
Date: Fri, 24 May 2019 17:30:49 +0200	[thread overview]
Message-ID: <CAKv+Gu_VqNa-Kg0Wo0rCYf0CUCx0yTGKsCUXHBRyEvtMN+OYWA@mail.gmail.com> (raw)
In-Reply-To: <06ce80d4-02da-4323-af3b-0d0f8be3f6eb@default>

(remove openssl user list)

On Wed, 22 May 2019 at 03:48, Paul Dale <paul.dale@oracle.com> wrote:
>
> Double makes sense.  Entropy is often estimated as a real value.
>
> E.g. we have the aforementioned coin flipper feeding data serially.
> Adding each bit sequentially means 0.125 bytes of entropy per call.
>
> Not the best example....
>

It looks like the people saying double is a good idea didn't actually
look at the code. The double argument is compared to a size_t cast to
double, and assigned that same value under some conditions.

I think the problem is that the double argument is part of the RAND
API, so they cannot easily change it.

  reply	other threads:[~2019-05-24 15:31 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-21 14:15 why does RAND_add() take "randomness" as a "double"? Laszlo Ersek
2019-05-21 17:00 ` [edk2-devel] " Laszlo Ersek
2019-05-22  1:48 ` Paul Dale
2019-05-24 15:30   ` Ard Biesheuvel [this message]
  -- strict thread matches above, loose matches on Subject: below --
2019-05-21 12:34 Laszlo Ersek

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