fix: doubling point error for twisted edwards projective

mratsim · Sep 21, 2023 · b6f4dde · b6f4dde
1 parent eeb2616
commit b6f4dde
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/constantine/math/elliptic/ec_twistededwards_projective.nim b/constantine/math/elliptic/ec_twistededwards_projective.nim
@@ -279,11 +279,11 @@ func double*[Field](
 
   # (B-C-D) => 2X1Y1, but With squaring and 2 substractions instead of mul + addition
   # In practice, squaring is not cheap enough to compasate the extra substraction cost.
+  E.square(P.x)
   r.x.prod(P.x, P.y)
   r.x.double()
 
   D.square(P.y)
-  E.square(P.x)
   E *= Field.C.getCoefA()
 
   r.y.sum(E, D)    # Ry stores F = E+D