ParagonIE_Sodium_Core_Curve25519::fe_normalize( ParagonIE_Sodium_Core_Curve25519_Fe $f ): ParagonIE_Sodium_Core_Curve25519_Fe

3816    public static function fe_normalize(ParagonIE_Sodium_Core_Curve25519_Fe $f)3817    {3818        $x = (PHP_INT_SIZE << 3) - 1; // 31 or 633819 3820        $g = self::fe_copy($f);3821        $e = array(3822            $g->e0, $g->e1, $g->e2, $g->e3, $g->e4,3823            $g->e5, $g->e6, $g->e7, $g->e8, $g->e93824        );3825        for ($i = 0; $i < 10; ++$i) {3826            $mask = -(($e[$i] >> $x) & 1);3827 3828            /*3829             * Get two candidate normalized values for $e[$i], depending on the sign of $e[$i]:3830             */3831            $a = $e[$i] & 0x7ffffff;3832            $b = -((-$e[$i]) & 0x7ffffff);3833 3834            /*3835             * Return the appropriate candidate value, based on the sign of the original input:3836             *3837             * The following is equivalent to this ternary:3838             *3839             * $e[$i] = (($e[$i] >> $x) & 1) ? $a : $b;3840             *3841             * Except what's written doesn't contain timing leaks.3842             */3843            $e[$i] = ($a ^ (($a ^ $b) & $mask));3844        }3845        $g->e0 = $e[0];3846        $g->e1 = $e[1];3847        $g->e2 = $e[2];3848        $g->e3 = $e[3];3849        $g->e4 = $e[4];3850        $g->e5 = $e[5];3851        $g->e6 = $e[6];3852        $g->e7 = $e[7];3853        $g->e8 = $e[8];3854        $g->e9 = $e[9];3855        return $g;3856    }