Re: [tsvwg] Mirja Kühlewind's No Objection on draft-ietf-tsvwg-tinymt32-02: (with COMMENT)

Vincent Roca <> Mon, 27 May 2019 09:21 UTC

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Date: Mon, 27 May 2019 11:21:06 +0200
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Subject: Re: [tsvwg] =?utf-8?q?Mirja_K=C3=BChlewind=27s_No_Objection_on_draft?= =?utf-8?q?-ietf-tsvwg-tinymt32-02=3A_=28with_COMMENT=29?=
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Dear Mirja and Eric

Thanks a lot for your comments.
I hereafter answer both of your comments since they are close to one another:

> Le 20 mai 2019 à 19:48, Mirja Kühlewind via Datatracker <> a écrit :
> Mirja Kühlewind has entered the following ballot position for
> draft-ietf-tsvwg-tinymt32-02: No Objection

> ----------------------------------------------------------------------
> ----------------------------------------------------------------------
> I agree with Eric that a reference to MT would be really good.

[VR] We added the seminal MT scientific publication.
There’s unfortunately nothing similar for the TinyMT variant.

> As mentioned in the intro, "neither TinyMT nor MT are meant to be used for
> cryptographic applications". Please add this also to the security
> considerations section and maybe further explain risks.

[VR] Done.

> Similar as the feedback originally provided (by other ADs) for
> draft-ietf-tsvwg-rlc-fec-scheme, I would prefer to have the algorithm specified
> in text and not only as code.

[VR] Sure, but in that case it is too risky (risk of introducing an error in the textual 
representation) and we left it as is.


> Le 18 mai 2019 à 18:41, Éric Vyncke via Datatracker <> a écrit :
> Éric Vyncke has entered the following ballot position for
> draft-ietf-tsvwg-tinymt32-02: No Objection
> ----------------------------------------------------------------------
> ----------------------------------------------------------------------
> Thanks for the work everyone has put into this document (and I understand that
> this -02 is coming out of another older document). While the mathematical
> aspects of the document are above my head, I took the liberty to put 3 comments
> and 1 nit in the hope to improve the quality of the document.
> == COMMENTS ==
> -- Introduction  --
> Why not using the usual format for informative references in this chapter?

[VR] Good point, it’s now implemented.

              Saito, M. and M. Matsumoto, "Tiny Mersenne Twister
              (TinyMT) github site", <

              Rikitake, K., "TinyMT pre-calculated parameter list github
              site", <>.

              Saito, M. and M. Matsumoto, "Tiny Mersenne Twister
              (TinyMT) web site",

> The Mersenne Twister is part of the sentence but there are no reference to any
> paper. Please add a reference for the seminal piece of work.

[VR] Done with the brand new [MT98] reference;

> "...TinyMT32 represents a major improvement ..." can we have more information
> about this improvment? On which aspect ?

[VR] Yes, we clarified it (already in version -02). 

   According to statistical tests (BigCrush in
   TestU01 and AdaptiveCrush), the quality of the outputs of TinyMT
   seems pretty good in terms of randomnes (in particular the uniformity
   of generated numbers), taking the small size of the internal state
   into consideration (see [TinyMT-web]).

We also added references to explain why Park-Miller PRNG should not be used.

   Miler Linear Congruential PRNG (e.g., as specified in [RFC5170]) that
   suffers several known limitations (see for instance [PTVF92], section
   7.1, p. 279, and [RLC-ID], Appendix B).

> == NITS ==
> -- Abstract  --
> I find it a little surprizing that two authors are cited in the abstract.

[VR] Yes, and we removed their names, adding only a reference to the academic

   This PRNG is a
   small-sized variant of Mersenne Twister (MT) PRNG [MT98].


  Vincent, on behalf of the authors