yplusx = $yplusx; if ($yminusx === null) { $yminusx = ParagonIE_Sodium_Core32_Curve25519::fe_0(); } $this->yminusx = $yminusx; if ($xy2d === null) { $xy2d = ParagonIE_Sodium_Core32_Curve25519::fe_0(); } $this->xy2d = $xy2d; } }