# Re: ECC point compression trick

*From*: Paul Rubin <http://phr.cx@xxxxxxxxxxxxxx>*Date*: Wed, 28 Jun 2006 15:50:39 GMT

"Tom St Denis" <tomstdenis@xxxxxxxxx> writes:

Why not always just use the positive root [adjusting your secret

multiplier as required since (-k)P == k(-P)].

In a finite field I'm not sure how you want to specify which root

is "positive".

You still have to compute the root to find y but now you don't even

send the one bit. You just send x.

You can already do that. See:

http://cr.yp.to/patents/us/6141420.html

.

**Follow-Ups**:**Re: ECC point compression trick***From:*Tom St Denis

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