Re: Researches in quantum computing seem to progress only extremely slowly

From	bartekltg <bartek@gmail.com>
Newsgroups	comp.programming
Subject	Re: Researches in quantum computing seem to progress only extremely slowly
Date	2015-09-03 00:35 +0200
Organization	Aioe.org NNTP Server
Message-ID	<ms7tk8$is0$1@speranza.aioe.org> (permalink)
References	(4 earlier) <ms6d4b$674$1@news.albasani.net> <20150902054403.661@kylheku.com> <ms7nf7$j4q$1@news.albasani.net> <c0reua9jbn013grv90b7bpckeq844ljfv6@4ax.com> <ms7ro4$qcm$1@news.albasani.net>

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On 03.09.2015 00:03, Mok-Kong Shen wrote:
> Am 02.09.2015 um 23:52 schrieb Robert Wessel:
>> On Wed, 2 Sep 2015 22:50:52 +0200, Mok-Kong Shen
>> <mok-kong.shen@t-online.de> wrote:
>>
>>> Am 02.09.2015 um 15:00 schrieb Kaz Kylheku:
>>>> On 2015-09-02, Mok-Kong Shen <mok-kong.shen@t-online.de> wrote:
>>>>> In my code PROVABLEPRIME
>>>>> (http://s13.zetaboards.com/Crypto/topic/7234475/1/) there is no seed
>>>>> to be input by the user at all. When the Python session starts, the
>>>>> system employs the current time to seed its built-in PRNG. So each
>>>>> time one uses the code to e.g. generate RSA keys, one gets a different
>>>>> pair by chance. Certainly one could question the security of that from
>>>>> an "exact" standpoint (I mean in the sense of proofs of pure math),
>>>>
>>>> The "exact standpoint" here is quite obvious and it is that a sample
>>>> of the
>>>> current time (even if it includes micro or nanoseconds from a high
>>>> resolution timer,
>>>> and not only the "seconds sine epoch" or whatever) simply has too
>>>> few bits of
>>>> entropy to generate good RSA keys.
>>>
>>> I must admit that I yet have doubt on such application of the entropy
>>> argument (i.e. without regard to how an amount of entropy is actually
>>> being employed in the processing) due to a paradox that I put up
>>> and described in a recent another thread: AES-128 in counter mode has
>>> an input of max 128 bits of entropy but its ouput is commonly used to
>>> e.g. xor n plaintext bits with n >> 128. The average entropy that is
>>> contained in one ciphertext bit thus can't be greater than 128/n,
>>> which is negligible for even moderately large n. Does that imply that
>>> AES in CTR mode is totally broken?
>>
>>
>> No, it simply means that you don't need to do more than about 2**128
>> work to break it with a known plaintext attack of sufficient size
>> (where "sufficient" may be as little as 16 bytes).  But that's not
>> broken, since that's what we were assuming anyway.  Sure, it's not a
>> OTP, but it was never meant to be.
>
> I don't yet understand. One expands a sequence of 128 bits somehow
> to a sequence of n bits with n >> 128. If the input 128 bits have
> a total "entropy" of 128, then it can certainly also be asked how
> much entropy the output n bits have in total and hence the average
> value of entropy of each output bit.

OK, this will be far from formal math...

Do you assume the text is known? If the entropy is only entropy
of the coding sequence, you do.
In the first 128 bits there is 128bit of enthropy.
In the second 128 bits there is 128bit of enthropy.
In the first 256 bits - 128 bits of enthropy.

The entropy of whole sequence (X,Y)
H(X,Y) = H(X) + H(Y|X)  (=H(y) + H(X|Y))
is equal to entropy of the first part plus
_conditional_ entropy od Y under the assumption X is known.
And because you use the same sequence to code the second half,
there is no new information. H(X|Y) = 0.



bartekltg

Thread

Researches in quantum computing seem to progress only extremely slowly Mok-Kong Shen <mok-kong.shen@t-online.de> - 2015-09-01 13:09 +0200
  Re: Researches in quantum computing seem to progress only extremely slowly Kaz Kylheku <kaz@kylheku.com> - 2015-09-01 14:23 +0000
    Re: Researches in quantum computing seem to progress only extremely slowly Mok-Kong Shen <mok-kong.shen@t-online.de> - 2015-09-01 20:00 +0200
      Re: Researches in quantum computing seem to progress only extremely slowly Kaz Kylheku <kaz@kylheku.com> - 2015-09-01 18:43 +0000
        Re: Researches in quantum computing seem to progress only extremely slowly Mok-Kong Shen <mok-kong.shen@t-online.de> - 2015-09-02 10:48 +0200
          Re: Researches in quantum computing seem to progress only extremely slowly Kaz Kylheku <kaz@kylheku.com> - 2015-09-02 13:00 +0000
            Re: Researches in quantum computing seem to progress only extremely slowly Mok-Kong Shen <mok-kong.shen@t-online.de> - 2015-09-02 22:50 +0200
              Re: Researches in quantum computing seem to progress only extremely slowly Kaz Kylheku <kaz@kylheku.com> - 2015-09-02 21:31 +0000
                Re: Researches in quantum computing seem to progress only extremely slowly Mok-Kong Shen <mok-kong.shen@t-online.de> - 2015-09-02 23:46 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly Kaz Kylheku <kaz@kylheku.com> - 2015-09-02 21:58 +0000
                Re: Researches in quantum computing seem to progress only extremely slowly Mok-Kong Shen <mok-kong.shen@t-online.de> - 2015-09-03 00:13 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly Kaz Kylheku <kaz@kylheku.com> - 2015-09-03 00:32 +0000
                Re: Researches in quantum computing seem to progress only extremely slowly Mok-Kong Shen <mok-kong.shen@t-online.de> - 2015-09-03 02:47 +0200
              Re: Researches in quantum computing seem to progress only extremely slowly Robert Wessel <robertwessel2@yahoo.com> - 2015-09-02 16:52 -0500
                Re: Researches in quantum computing seem to progress only extremely slowly Mok-Kong Shen <mok-kong.shen@t-online.de> - 2015-09-03 00:03 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly Robert Wessel <robertwessel2@yahoo.com> - 2015-09-02 17:18 -0500
                Re: Researches in quantum computing seem to progress only extremely slowly Mok-Kong Shen <mok-kong.shen@t-online.de> - 2015-09-03 00:28 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly Robert Wessel <robertwessel2@yahoo.com> - 2015-09-02 17:52 -0500
                Re: Researches in quantum computing seem to progress only extremely slowly bartekltg <bartek@gmail.com> - 2015-09-03 01:04 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly Robert Wessel <robertwessel2@yahoo.com> - 2015-09-02 18:29 -0500
                Re: Researches in quantum computing seem to progress only extremely slowly Mok-Kong Shen <mok-kong.shen@t-online.de> - 2015-09-03 01:04 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly Robert Wessel <robertwessel2@yahoo.com> - 2015-09-02 18:25 -0500
                Re: Researches in quantum computing seem to progress only extremely slowly Mok-Kong Shen <mok-kong.shen@t-online.de> - 2015-09-03 01:33 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly Robert Wessel <robertwessel2@yahoo.com> - 2015-09-02 18:53 -0500
                Re: Researches in quantum computing seem to progress only extremely slowly Mok-Kong Shen <mok-kong.shen@t-online.de> - 2015-09-03 02:16 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly Mok-Kong Shen <mok-kong.shen@t-online.de> - 2015-09-03 02:18 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly bartekltg <bartek@gmail.com> - 2015-09-03 02:33 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly Mok-Kong Shen <mok-kong.shen@t-online.de> - 2015-09-03 02:42 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly bartekltg <bartek@gmail.com> - 2015-09-03 02:55 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly Mok-Kong Shen <mok-kong.shen@t-online.de> - 2015-09-03 03:03 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly bartekltg <bartek@gmail.com> - 2015-09-03 03:14 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly Mok-Kong Shen <mok-kong.shen@t-online.de> - 2015-09-03 03:17 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly bartekltg <bartek@gmail.com> - 2015-09-03 03:30 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly Mok-Kong Shen <mok-kong.shen@t-online.de> - 2015-09-03 03:36 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly bartekltg <bartek@gmail.com> - 2015-09-03 04:13 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly Mok-Kong Shen <mok-kong.shen@t-online.de> - 2015-09-03 04:19 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly bartekltg <bartek@gmail.com> - 2015-09-03 04:32 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly Robert Wessel <robertwessel2@yahoo.com> - 2015-09-02 22:51 -0500
                Re: Researches in quantum computing seem to progress only extremely slowly Mok-Kong Shen <mok-kong.shen@t-online.de> - 2015-09-03 16:51 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly Robert Wessel <robertwessel2@yahoo.com> - 2015-09-03 10:49 -0500
                Re: Researches in quantum computing seem to progress only extremely slowly Mok-Kong Shen <mok-kong.shen@t-online.de> - 2015-09-04 19:47 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly Robert Wessel <robertwessel2@yahoo.com> - 2015-09-04 13:42 -0500
                Re: Researches in quantum computing seem to progress only extremely slowly Mok-Kong Shen <mok-kong.shen@t-online.de> - 2015-09-04 21:50 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly Kaz Kylheku <kaz@kylheku.com> - 2015-09-04 20:33 +0000
                Re: Researches in quantum computing seem to progress only extremely slowly Mok-Kong Shen <mok-kong.shen@t-online.de> - 2015-09-04 23:45 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly bartekltg <bartek@gmail.com> - 2015-09-05 01:24 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly Robert Wessel <robertwessel2@yahoo.com> - 2015-09-07 00:50 -0500
                Re: Researches in quantum computing seem to progress only extremely slowly Mok-Kong Shen <mok-kong.shen@t-online.de> - 2015-09-07 14:14 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly bartekltg <bartek@gmail.com> - 2015-09-07 15:57 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly Robert Wessel <robertwessel2@yahoo.com> - 2015-09-07 12:19 -0500
                Re: Researches in quantum computing seem to progress only extremely slowly Mok-Kong Shen <mok-kong.shen@t-online.de> - 2015-09-08 23:47 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly bartekltg <bartek@gmail.com> - 2015-09-09 02:28 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly Kaz Kylheku <kaz@kylheku.com> - 2015-09-04 20:23 +0000
                Re: Researches in quantum computing seem to progress only extremely slowly bartekltg <bartek@gmail.com> - 2015-09-05 00:55 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly "Chris M. Thomasson" <nospam@nospam.nospam> - 2015-09-04 17:11 -0700
                Re: Researches in quantum computing seem to progress only extremely slowly bartekltg <bartek@gmail.com> - 2015-09-05 02:31 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly "Chris M. Thomasson" <nospam@nospam.nospam> - 2015-09-04 20:15 -0700
                Re: Researches in quantum computing seem to progress only extremely slowly bartekltg <bartek@gmail.com> - 2015-09-03 00:35 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly bartekltg <bartek@gmail.com> - 2015-09-03 00:42 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly Mok-Kong Shen <mok-kong.shen@t-online.de> - 2015-09-03 00:46 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly bartekltg <bartek@gmail.com> - 2015-09-03 00:54 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly Mok-Kong Shen <mok-kong.shen@t-online.de> - 2015-09-03 01:11 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly bartekltg <bartek@gmail.com> - 2015-09-03 01:21 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly Mok-Kong Shen <mok-kong.shen@t-online.de> - 2015-09-03 01:28 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly bartekltg <bartek@gmail.com> - 2015-09-03 02:01 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly Mok-Kong Shen <mok-kong.shen@t-online.de> - 2015-09-03 02:22 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly bartekltg <bartek@gmail.com> - 2015-09-03 02:51 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly Mok-Kong Shen <mok-kong.shen@t-online.de> - 2015-09-03 02:57 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly bartekltg <bartek@gmail.com> - 2015-09-03 03:08 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly Mok-Kong Shen <mok-kong.shen@t-online.de> - 2015-09-03 03:31 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly bartekltg <bartek@gmail.com> - 2015-09-03 03:45 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly Mok-Kong Shen <mok-kong.shen@t-online.de> - 2015-09-03 03:54 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly bartekltg <bartek@gmail.com> - 2015-09-03 04:18 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly Mok-Kong Shen <mok-kong.shen@t-online.de> - 2015-09-03 04:24 +0200
                Re: Researches in quantum computing seem to progress only extremely slowly Johannes Bauer <dfnsonfsduifb@gmx.de> - 2015-09-03 07:23 +0200
          Re: Researches in quantum computing seem to progress only extremely slowly Robert Wessel <robertwessel2@yahoo.com> - 2015-09-02 16:14 -0500
            Re: Researches in quantum computing seem to progress only extremely slowly Mok-Kong Shen <mok-kong.shen@t-online.de> - 2015-09-02 23:23 +0200
              Re: Researches in quantum computing seem to progress only extremely slowly Kaz Kylheku <kaz@kylheku.com> - 2015-09-02 21:33 +0000
                Re: Researches in quantum computing seem to progress only extremely slowly Mok-Kong Shen <mok-kong.shen@t-online.de> - 2015-09-02 23:54 +0200
          Re: Researches in quantum computing seem to progress only extremely slowly bartekltg <bartek@gmail.com> - 2015-09-02 23:22 +0200
            Re: Researches in quantum computing seem to progress only extremely slowly Mok-Kong Shen <mok-kong.shen@t-online.de> - 2015-09-02 23:32 +0200
              Re: Researches in quantum computing seem to progress only extremely slowly bartekltg <bartek@gmail.com> - 2015-09-03 00:22 +0200
  Re: Researches in quantum computing seem to progress only extremely slowly "Chris M. Thomasson" <nospam@nospam.nospam> - 2015-09-01 13:23 -0700
    Re: Researches in quantum computing seem to progress only extremely slowly Mok-Kong Shen <mok-kong.shen@t-online.de> - 2015-09-02 11:04 +0200
  Re: Researches in quantum computing seem to progress only extremely slowly Robert Wessel <robertwessel2@yahoo.com> - 2015-09-02 02:22 -0500

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