From: Richard Moore <me@ricmoo.com>
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Date: Sat, 19 Jul 2014 00:33:13 -0400
To: Bitcoin Dev <bitcoin-development@lists.sourceforge.net>
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Subject: [Bitcoin-development] Signature with negative integer?
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Hey all,

I'm wondering if anyone can help explain to me tx =
70f7c15c6f62139cc41afa858894650344eda9975b46656d893ee59df8914a3d...

=
(https://blockchain.info/tx/70f7c15c6f62139cc41afa858894650344eda9975b4665=
6d893ee59df8914a3d)


The input signature script is:

=
304402206b5c3b1c86748dcf328b9f3a65e10085afcf5d1af5b40970d8ce3a9355e06b5b02=
20cdbdc23e6d3618e47056fccc60c5f73d1a542186705197e5791e97f0e6582a3201=20


Which decodes to:

r=3D =
48560432700441876832361368709121298776045893858160378595187765610521057848=
155
s=3D =
-2273268056069420633219046805863866475002741811419506837553814464054943389=
0254

=
(http://lapo.it/asn1js/#304402206B5C3B1C86748DCF328B9F3A65E10085AFCF5D1AF5=
B40970D8CE3A9355E06B5B0220CDBDC23E6D3618E47056FCCC60C5F73D1A542186705197E5=
791E97F0E6582A32)


The ECC library I'm using is failing to verify this, which I think makes =
sense, since I the point needs to be positive, no? But it is obviously =
valid, as it has been verified and spent. I have tried simply modulo =
curve.order to positive-ify it, but that didn't seem to work either. =
Given a point P (with Py < 0) is there some fancy way to bring it into =
the elliptic curve space, such that Px >=3D 0 and Py >=3D 0?

Thanks!

RicMoo


.=B7=B4=AF`=B7.=B8=B8.=B7=B4=AF`=B7.=B8=B8.=B7=B4=AF`=B7.=B8=B8.=B7=B4=AF`=
=B7.=B8=B8.=B7=B4=AF`=B7.=B8><(((=BA>

Richard Moore ~ Founder
Genetic Mistakes Software inc.
phone: (778) 882-6125
email: ricmoo@geneticmistakes.com
www: http://GeneticMistakes.com