Re: ECC point compression trick

"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
.