[PATCH] Add gcry_mpi_ec_sub.

Markus Teich teichm at in.tum.de
Tue Jul 22 10:50:43 CEST 2014

Ian Goldberg wrote:
> Wait: isn't the negation of a point (x,y) on a twisted Edwards curve
> the point (-x,y)?  You're calculating (x,-y) above, it seems to me.


indeed I am calculating (x,-y). I took Appendix A from the Curve 25519 paper[0]
as reference. If that is indeed wrong, I will of course amend the patch.


[0] http://cr.yp.to/ecdh/curve25519-20060209.pdf

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