/home/kueuepay/public_html/vendor/pragmarx/google2fa/src/Google2FA.php
<?php

namespace PragmaRX\Google2FA;

use PragmaRX\Google2FA\Exceptions\InvalidAlgorithmException;
use PragmaRX\Google2FA\Exceptions\SecretKeyTooShortException;
use PragmaRX\Google2FA\Support\Base32;
use PragmaRX\Google2FA\Support\Constants;
use PragmaRX\Google2FA\Support\QRCode;

class Google2FA
{
    use QRCode;
    use Base32;

    /**
     * Algorithm.
     *
     * @var string
     */
    protected $algorithm = Constants::SHA1;

    /**
     * Length of the Token generated.
     *
     * @var int
     */
    protected $oneTimePasswordLength = 6;

    /**
     * Interval between key regeneration.
     *
     * @var int
     */
    protected $keyRegeneration = 30;

    /**
     * Secret.
     *
     * @var string
     */
    protected $secret;

    /**
     * Window.
     *
     * @var int
     */
    protected $window = 1; // Keys will be valid for 60 seconds

    /**
     * Find a valid One Time Password.
     *
     * @param string   $secret
     * @param string   $key
     * @param int|null $window
     * @param int      $startingTimestamp
     * @param int      $timestamp
     * @param int|null $oldTimestamp
     *
     * @throws \PragmaRX\Google2FA\Exceptions\SecretKeyTooShortException
     * @throws \PragmaRX\Google2FA\Exceptions\InvalidCharactersException
     * @throws \PragmaRX\Google2FA\Exceptions\IncompatibleWithGoogleAuthenticatorException
     *
     * @return bool|int
     */
    public function findValidOTP(
        $secret,
        $key,
        $window,
        $startingTimestamp,
        $timestamp,
        $oldTimestamp = null
    ) {
        for (;
            $startingTimestamp <= $timestamp + $this->getWindow($window);
            $startingTimestamp++
        ) {
            if (
                hash_equals($this->oathTotp($secret, $startingTimestamp), $key)
            ) {
                return is_null($oldTimestamp)
                    ? true
                    : $startingTimestamp;
            }
        }

        return false;
    }

    /**
     * Generate the HMAC OTP.
     *
     * @param string $secret
     * @param int    $counter
     *
     * @return string
     */
    protected function generateHotp($secret, $counter)
    {
        return hash_hmac(
            $this->getAlgorithm(),
            pack('N*', 0, $counter), // Counter must be 64-bit int
            $secret,
            true
        );
    }

    /**
     * Generate a digit secret key in base32 format.
     *
     * @param int    $length
     * @param string $prefix
     *
     * @throws \PragmaRX\Google2FA\Exceptions\IncompatibleWithGoogleAuthenticatorException
     * @throws \PragmaRX\Google2FA\Exceptions\InvalidCharactersException
     * @throws \PragmaRX\Google2FA\Exceptions\SecretKeyTooShortException
     *
     * @return string
     */
    public function generateSecretKey($length = 16, $prefix = '')
    {
        return $this->generateBase32RandomKey($length, $prefix);
    }

    /**
     * Get the current one time password for a key.
     *
     * @param string $secret
     *
     * @throws \PragmaRX\Google2FA\Exceptions\SecretKeyTooShortException
     * @throws \PragmaRX\Google2FA\Exceptions\InvalidCharactersException
     * @throws \PragmaRX\Google2FA\Exceptions\IncompatibleWithGoogleAuthenticatorException
     *
     * @return string
     */
    public function getCurrentOtp($secret)
    {
        return $this->oathTotp($secret, $this->getTimestamp());
    }

    /**
     * Get the HMAC algorithm.
     *
     * @return string
     */
    public function getAlgorithm()
    {
        return $this->algorithm;
    }

    /**
     * Get key regeneration.
     *
     * @return int
     */
    public function getKeyRegeneration()
    {
        return $this->keyRegeneration;
    }

    /**
     * Get OTP length.
     *
     * @return int
     */
    public function getOneTimePasswordLength()
    {
        return $this->oneTimePasswordLength;
    }

    /**
     * Get secret.
     *
     * @param string|null $secret
     *
     * @return string
     */
    public function getSecret($secret = null)
    {
        return is_null($secret) ? $this->secret : $secret;
    }

    /**
     * Returns the current Unix Timestamp divided by the $keyRegeneration
     * period.
     *
     * @return int
     **/
    public function getTimestamp()
    {
        return (int) floor(microtime(true) / $this->keyRegeneration);
    }

    /**
     * Get a list of valid HMAC algorithms.
     *
     * @return array
     */
    protected function getValidAlgorithms()
    {
        return [
            Constants::SHA1,
            Constants::SHA256,
            Constants::SHA512,
        ];
    }

    /**
     * Get the OTP window.
     *
     * @param null|int $window
     *
     * @return int
     */
    public function getWindow($window = null)
    {
        return is_null($window) ? $this->window : $window;
    }

    /**
     * Make a window based starting timestamp.
     *
     * @param int|null $window
     * @param int      $timestamp
     * @param int|null $oldTimestamp
     *
     * @return mixed
     */
    private function makeStartingTimestamp($window, $timestamp, $oldTimestamp = null)
    {
        return is_null($oldTimestamp)
            ? $timestamp - $this->getWindow($window)
            : max($timestamp - $this->getWindow($window), $oldTimestamp + 1);
    }

    /**
     * Get/use a starting timestamp for key verification.
     *
     * @param string|int|null $timestamp
     *
     * @return int
     */
    protected function makeTimestamp($timestamp = null)
    {
        if (is_null($timestamp)) {
            return $this->getTimestamp();
        }

        return (int) $timestamp;
    }

    /**
     * Takes the secret key and the timestamp and returns the one time
     * password.
     *
     * @param string $secret  Secret key in binary form.
     * @param int    $counter Timestamp as returned by getTimestamp.
     *
     * @throws \PragmaRX\Google2FA\Exceptions\SecretKeyTooShortException
     * @throws \PragmaRX\Google2FA\Exceptions\InvalidCharactersException
     * @throws Exceptions\IncompatibleWithGoogleAuthenticatorException
     *
     * @return string
     */
    public function oathTotp($secret, $counter)
    {
        if (strlen($secret) < 8) {
            throw new SecretKeyTooShortException();
        }

        $secret = $this->base32Decode($this->getSecret($secret));

        return str_pad(
            $this->oathTruncate($this->generateHotp($secret, $counter)),
            $this->getOneTimePasswordLength(),
            '0',
            STR_PAD_LEFT
        );
    }

    /**
     * Extracts the OTP from the SHA1 hash.
     *
     * @param string $hash
     *
     * @return string
     **/
    public function oathTruncate($hash)
    {
        $offset = ord($hash[strlen($hash) - 1]) & 0xF;

        $temp = unpack('N', substr($hash, $offset, 4));

        $temp = $temp[1] & 0x7FFFFFFF;

        return substr(
            (string) $temp,
            -$this->getOneTimePasswordLength()
        );
    }

    /**
     * Remove invalid chars from a base 32 string.
     *
     * @param string $string
     *
     * @return string|null
     */
    public function removeInvalidChars($string)
    {
        return preg_replace(
            '/[^'.Constants::VALID_FOR_B32.']/',
            '',
            $string
        );
    }

    /**
     * Setter for the enforce Google Authenticator compatibility property.
     *
     * @param mixed $enforceGoogleAuthenticatorCompatibility
     *
     * @return $this
     */
    public function setEnforceGoogleAuthenticatorCompatibility(
        $enforceGoogleAuthenticatorCompatibility
    ) {
        $this->enforceGoogleAuthenticatorCompatibility = $enforceGoogleAuthenticatorCompatibility;

        return $this;
    }

    /**
     * Set the HMAC hashing algorithm.
     *
     * @param mixed $algorithm
     *
     * @throws \PragmaRX\Google2FA\Exceptions\InvalidAlgorithmException
     *
     * @return \PragmaRX\Google2FA\Google2FA
     */
    public function setAlgorithm($algorithm)
    {
        // Default to SHA1 HMAC algorithm
        if (!in_array($algorithm, $this->getValidAlgorithms())) {
            throw new InvalidAlgorithmException();
        }

        $this->algorithm = $algorithm;

        return $this;
    }

    /**
     * Set key regeneration.
     *
     * @param mixed $keyRegeneration
     */
    public function setKeyRegeneration($keyRegeneration)
    {
        $this->keyRegeneration = $keyRegeneration;
    }

    /**
     * Set OTP length.
     *
     * @param mixed $oneTimePasswordLength
     */
    public function setOneTimePasswordLength($oneTimePasswordLength)
    {
        $this->oneTimePasswordLength = $oneTimePasswordLength;
    }

    /**
     * Set secret.
     *
     * @param mixed $secret
     */
    public function setSecret($secret)
    {
        $this->secret = $secret;
    }

    /**
     * Set the OTP window.
     *
     * @param mixed $window
     */
    public function setWindow($window)
    {
        $this->window = $window;
    }

    /**
     * Verifies a user inputted key against the current timestamp. Checks $window
     * keys either side of the timestamp.
     *
     * @param string   $key          User specified key
     * @param string   $secret
     * @param null|int $window
     * @param null|int $timestamp
     * @param null|int $oldTimestamp
     *
     * @throws \PragmaRX\Google2FA\Exceptions\SecretKeyTooShortException
     * @throws \PragmaRX\Google2FA\Exceptions\InvalidCharactersException
     * @throws \PragmaRX\Google2FA\Exceptions\IncompatibleWithGoogleAuthenticatorException
     *
     * @return bool|int
     */
    public function verify(
        $key,
        $secret,
        $window = null,
        $timestamp = null,
        $oldTimestamp = null
    ) {
        return $this->verifyKey(
            $secret,
            $key,
            $window,
            $timestamp,
            $oldTimestamp
        );
    }

    /**
     * Verifies a user inputted key against the current timestamp. Checks $window
     * keys either side of the timestamp.
     *
     * @param string   $secret
     * @param string   $key          User specified key
     * @param int|null $window
     * @param null|int $timestamp
     * @param null|int $oldTimestamp
     *
     * @throws \PragmaRX\Google2FA\Exceptions\SecretKeyTooShortException
     * @throws \PragmaRX\Google2FA\Exceptions\InvalidCharactersException
     * @throws \PragmaRX\Google2FA\Exceptions\IncompatibleWithGoogleAuthenticatorException
     *
     * @return bool|int
     */
    public function verifyKey(
        $secret,
        $key,
        $window = null,
        $timestamp = null,
        $oldTimestamp = null
    ) {
        $timestamp = $this->makeTimestamp($timestamp);

        return $this->findValidOTP(
            $secret,
            $key,
            $window,
            $this->makeStartingTimestamp($window, $timestamp, $oldTimestamp),
            $timestamp,
            $oldTimestamp
        );
    }

    /**
     * Verifies a user inputted key against the current timestamp. Checks $window
     * keys either side of the timestamp, but ensures that the given key is newer than
     * the given oldTimestamp. Useful if you need to ensure that a single key cannot
     * be used twice.
     *
     * @param string   $secret
     * @param string   $key          User specified key
     * @param int|null $oldTimestamp The timestamp from the last verified key
     * @param int|null $window
     * @param int|null $timestamp
     *
     * @throws \PragmaRX\Google2FA\Exceptions\SecretKeyTooShortException
     * @throws \PragmaRX\Google2FA\Exceptions\InvalidCharactersException
     * @throws \PragmaRX\Google2FA\Exceptions\IncompatibleWithGoogleAuthenticatorException
     *
     * @return bool|int
     */
    public function verifyKeyNewer(
        $secret,
        $key,
        $oldTimestamp,
        $window = null,
        $timestamp = null
    ) {
        return $this->verifyKey(
            $secret,
            $key,
            $window,
            $timestamp,
            $oldTimestamp
        );
    }
}
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About NFC Pay: Our Story and Mission

NFC Pay was founded with a vision to transform the way people handle transactions. Our journey is defined by a commitment to innovation, security, and convenience. We strive to deliver seamless, user-friendly payment solutions that make everyday transactions effortless and secure. Our mission is to empower you to pay with ease and confidence, anytime, anywhere.

  • Simplifying Payments, One Tap at a Time.
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  • Smart Payments for a Effortless Lifestyle.
  • Experience the Ease of Tap and Pay.
  • Innovative Solutions for Your Daily Transactions.

Frequently Asked Questions About NFC Pay

Here are answers to some common questions about NFC Pay. We aim to provide clear and concise information to help you understand how our platform works and how it can benefit you. If you have any further inquiries, please don’t hesitate to contact our support team.

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How do I register for NFC Pay?

Download the app and sign up using your email or phone number, then complete the verification process.

Is my payment information secure?

Yes, we use advanced encryption and security protocols to protect your payment details.

Can I add multiple cards to my NFC Pay wallet?

Absolutely, you can link multiple debit or credit cards to your wallet.

How do I transfer money to another user?

Go to the transfer section, select the recipient, enter the amount, and authorize the transfer.

What should I do if I forget my PIN?

Use the “Forgot PIN” feature in the app to reset it following the provided instructions.

How can I activate my merchant account?

Sign up for a merchant account through the app and follow the setup instructions to start accepting payments.

Can I track my payment status?

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