ParagonIE_Sodium_Core_Curve25519

16abstract class ParagonIE_Sodium_Core_Curve25519 extends ParagonIE_Sodium_Core_Curve25519_H17{18    /**19     * Get a field element of size 10 with a value of 020     *21     * @internal You should not use this directly from another application22     *23     * @return ParagonIE_Sodium_Core_Curve25519_Fe24     */25    public static function fe_0()26    {27        return ParagonIE_Sodium_Core_Curve25519_Fe::fromArray(28            array(0, 0, 0, 0, 0, 0, 0, 0, 0, 0)29        );30    }31 32    /**33     * Get a field element of size 10 with a value of 134     *35     * @internal You should not use this directly from another application36     *37     * @return ParagonIE_Sodium_Core_Curve25519_Fe38     */39    public static function fe_1()40    {41        return ParagonIE_Sodium_Core_Curve25519_Fe::fromArray(42            array(1, 0, 0, 0, 0, 0, 0, 0, 0, 0)43        );44    }45 46    /**47     * Add two field elements.48     *49     * @internal You should not use this directly from another application50     *51     * @param ParagonIE_Sodium_Core_Curve25519_Fe $f52     * @param ParagonIE_Sodium_Core_Curve25519_Fe $g53     * @return ParagonIE_Sodium_Core_Curve25519_Fe54     * @psalm-suppress MixedAssignment55     * @psalm-suppress MixedOperand56     */57    public static function fe_add(58        ParagonIE_Sodium_Core_Curve25519_Fe $f,59        ParagonIE_Sodium_Core_Curve25519_Fe $g60    ) {61        /** @var array<int, int> $arr */62        $arr = array();63        for ($i = 0; $i < 10; ++$i) {64            $arr[$i] = (int) ($f[$i] + $g[$i]);65        }66        return ParagonIE_Sodium_Core_Curve25519_Fe::fromArray($arr);67    }68 69    /**70     * Constant-time conditional move.71     *72     * @internal You should not use this directly from another application73     *74     * @param ParagonIE_Sodium_Core_Curve25519_Fe $f75     * @param ParagonIE_Sodium_Core_Curve25519_Fe $g76     * @param int $b77     * @return ParagonIE_Sodium_Core_Curve25519_Fe78     * @psalm-suppress MixedAssignment79     */80    public static function fe_cmov(81        ParagonIE_Sodium_Core_Curve25519_Fe $f,82        ParagonIE_Sodium_Core_Curve25519_Fe $g,83        $b = 084    ) {85        /** @var array<int, int> $h */86        $h = array();87        $b *= -1;88        for ($i = 0; $i < 10; ++$i) {89            $x = (($f[$i] ^ $g[$i]) & $b);90            $h[$i] = ($f[$i]) ^ $x;91        }92        return ParagonIE_Sodium_Core_Curve25519_Fe::fromArray($h);93    }94 95    /**