Re: [hybi] "fresh" and "uniformly at random":

Adam Barth <ietf@adambarth.com> Mon, 20 June 2011 08:05 UTC

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From: Adam Barth <ietf@adambarth.com>
Date: Mon, 20 Jun 2011 01:05:23 -0700
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To: Denis Lagno <dilmah@chromium.org>
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Subject: Re: [hybi] "fresh" and "uniformly at random":
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Yeah, that was a confusing way of putting it.  I meant that the
underlying coin-flips should not have been used previously.

Adam


On Mon, Jun 20, 2011 at 12:34 AM, Denis Lagno <dilmah@chromium.org> wrote:
> oh, well, so you'd better avoid phrase "not used previously" in the
> first place.  It was highly misleading.
>
> On Mon, Jun 20, 2011 at 11:31 AM, Adam Barth <ietf@adambarth.com> wrote:
>> You can sensibly apply the term fresh to 1-bit values if you like.
>> The important aspect is independence from your previous choices.
>>
>> Adam
>>
>>
>> On Mon, Jun 20, 2011 at 12:26 AM, Denis Lagno <dilmah@chromium.org> wrote:
>>> maybe I miss something but in the text "fresh" is applied to 32-bit values..
>>>
>>> On Mon, Jun 20, 2011 at 6:57 AM, Adam Barth <ietf@adambarth.com> wrote:
>>>> On Sat, Jun 18, 2011 at 12:34 AM, Denis Lagno <dilmah@chromium.org> wrote:
>>>>> On Sat, Jun 18, 2011 at 10:27 AM, Adam Barth <ietf@adambarth.com> wrote:
>>>>>> The term "fresh" is a term of art in cryptography.  It means, roughly,
>>>>>> "not used previously."
>>>>>
>>>>> So this implies that client must keep track of already used keys? it
>>>>> imposes limit on length of connection?
>>>>> True it or false, It should be explicitly clarified in the text.
>>>>
>>>> The normal practice in cryptography is to just use large enough values
>>>> such that the probably of collision is sufficiently small as to be
>>>> acceptable.  For example, if you use a 20 byte nonce, the probably of
>>>> collision is zero for all practical purposes.
>>>>
>>>> This stuff is all extremely normal.
>>>>
>>>> Adam
>>>>
>>>
>>
>