ge_frombytes_negate_vartime example

/** * @param string $pk * @return string * @throws SodiumException * @throws TypeError */
    public static function pk_to_curve25519($pk)
    {
        if (self::small_order($pk)) {
            throw new SodiumException('Public key is on a small order');
        }
        $A = self::ge_frombytes_negate_vartime($pk);
        $p1 = self::ge_mul_l($A);
        if (!self::fe_isnonzero($p1->X)) {
            throw new SodiumException('Unexpected zero result');
        }

        # fe_1(one_minus_y);         # fe_sub(one_minus_y, one_minus_y, A.Y);         # fe_invert(one_minus_y, one_minus_y);         $one_minux_y = self::fe_invert(
            self::fe_sub(
                self::fe_1(),
                

/** * @param string $pk * @return string * @throws SodiumException * @throws TypeError */
    public static function pk_to_curve25519($pk)
    {
        if (self::small_order($pk)) {
            throw new SodiumException('Public key is on a small order');
        }
        $A = self::ge_frombytes_negate_vartime(self::substr($pk, 0, 32));
        $p1 = self::ge_mul_l($A);
        if (!self::fe_isnonzero($p1->X)) {
            throw new SodiumException('Unexpected zero result');
        }

        # fe_1(one_minus_y);         # fe_sub(one_minus_y, one_minus_y, A.Y);         # fe_invert(one_minus_y, one_minus_y);         $one_minux_y = self::fe_invert(
            self::fe_sub(
                self::fe_1(),
                

if (!is_resource($fp)) {
            throw new SodiumException('Could not open input file for reading');
        }

        /** @var bool The original value of ParagonIE_Sodium_Compat::$fastMult */
        $orig = ParagonIE_Sodium_Compat::$fastMult;

        // Set ParagonIE_Sodium_Compat::$fastMult to true to speed up verification.         ParagonIE_Sodium_Compat::$fastMult = true;

        /** @var ParagonIE_Sodium_Core_Curve25519_Ge_P3 $A */
        $A = ParagonIE_Sodium_Core_Ed25519::ge_frombytes_negate_vartime($publicKey);

        $hs = hash_init('sha512');
        self::hash_update($hs, self::substr($sig, 0, 32));
        self::hash_update($hs, self::substr($publicKey, 0, 32));
        /** @var resource $hs */
        $hs = self::updateHashWithFile($hs, $fp, $size);
        /** @var string $hDigest */
        $hDigest = hash_final($hs, true);

        /** @var string $h */
        $h = ParagonIE_Sodium_Core_Ed25519::sc_reduce($hDigest) . self::substr($hDigest, 32);