Re: [Cfrg] Comb algorithm IPR status (was: Results of the poll: Elliptic Curves - preferred curves around 256bit work factor (ends on March 3rd))

Alyssa Rowan <akr@akr.io> Fri, 06 March 2015 01:41 UTC

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Date: Fri, 06 Mar 2015 01:41:14 +0000
From: Alyssa Rowan <akr@akr.io>
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Subject: Re: [Cfrg] Comb algorithm IPR status (was: Results of the poll: Elliptic Curves - preferred curves around 256bit work factor (ends on March 3rd))
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> [BB] What happened to the earlier, vigorous arguments by Robert 
> Ransom, Alyssa Rowan and Mike Hamburg that Goldilocks448, and 
> perhaps all of the curves based on large primes, would be covered 
> by Microsoft IP?

I don't recall saying that. Perhaps you misunderstood?

> [MH] …Alyssa and I just want to make sure that the patent
> landscape is clear so that nobody infringes by accident.

Mike is correct. It wasn't the curves in the (now-expired) NUMS draft
that concerned me, but that we might've chosen curves based on
benchmarked reference implementations covered by undisclosed patents. It
would have been a problem if the only elegant implementations of the
curves we'd picked were patented. Fortunately, that is not the case!

> [MH] Since my code uses signed all-bits set combs, and if I 
> understand correctly your patent specifically covers modified 
> LSB-set combs, I don’t believe that my implementation has patent 
> problems. Again, this is a property of the implementation and not 
> of the curve.

The advice I have received matches Mike's (and my) interpretation -
I don't think Ed448-Goldilocks (the curve or reference implementation)
has any IPR problems (although I obviously cannot make any warranties or
guarantees!).

>> [MH] Nearly 6 months have passed and we haven’t heard anything 
>> from legal. Do you have an update for us?
> [BB] I cannot comment on Microsoft as I am no longer there.

Noted.

Perhaps the other co-authors of the (expired) NUMS draft could?

- -- 
/akr
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