Re: [Cfrg] Patents and the new elliptic curves

Mike,

As I explained in that formerly private discussion, we have asked for an
internal legal review on US7602907 as we were unaware of it at the time the
code and drafts were written. I am not in a position to comment on whether
it is a concern, and until that review is complete there is nothing for
anyone to confirm or deny.

Large companies work this way, including that avoidance of reading patents
to limit exposure in the event of IP litigation. While bashing Microsoft
and its employees seems to never go out of fashion, it is not merely
unhelpful, but counterproductive and inappropriate here. We are
participating in this process in good faith and assume everyone else is, as
well, even if there are points of disagreement.

It does strike me as odd you are criticizing us for not doing extensive
patent searches when you haven't done so and BCP 79 does not require it. I
hope everyone will be held to the same standard here, whatever it is.

b

On Tue, Sep 16, 2014 at 2:56 PM, Michael Hamburg <mike@shiftleft.org> wrote:

> Hello CFRG,
>
> I’m concerned about patent issues which may affect the new elliptic curve
> standards.
>
> There has been a side discussion involving several members of this list,
> including some Microsoft researchers, on the subject of what patents may
> apply to proposed curves and their implementations and in particular to the
> NUMS curves.
>
> Microsoft has a policy of avoiding patent searches, not reading patents,
> not commenting on patents etc, so they have not been particularly helpful.
> However, I am concerned that the Microsoft-held US7602907 (and possibly
> foreign equivalents) may apply to their implementation, covering the mLSB
> combs algorithm.  Benjamin Black has refused to confirm or deny this.  The
> NUMS code itself is still usable under the Apache2 license, but it has a
> "mutually assured destruction” clause, and other implementations might
> infringe.
>
> So I have a few questions for the list.  First, am I right to be concerned
> that US7602907 reads against the NUMS code?  How does this interact with
> the BCP, since the curve’s spec does not require the patent, but the
> reference implementation does?
>
> Second, is anyone aware of other patents that may read on SafeCurves-style
> Montgomery or (twisted) Edwards implementations, especially of the proposed
> curves (\w+)25519, Curve41417, MS NUMS, Ed448-Goldilocks or E-521?  It is
> required that new curves be efficiently and securely implementable without
> stepping on such patents, so it is critical to know what they are.
>
> Third, given that mLSB combs may be encumbered, does anyone have
> information on the patent status of other state-of-the-art comb
> algorithms?  I’m particularly hoping that the signed all bits set (SABS)
> combs algorithm used in Goldilocks is patent-free, but I have only
> conducted a limited search.
>
> Thanks,
> — Mike Hamburg
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