PragmaRX\Google2FA\Google2FA

Complexity

Total Complexity

29

Size/Duplication

Total Lines	338
Duplicated Lines	0 %

Coupling/Cohesion

Components	1
Dependencies	3

Importance

Changes	11
Bugs	3	Features	0

21 Methods

Rating	Name	Duplication	Size	Complexity
A	generateSecretKey()	0	4	1
A	getKeyRegeneration()	0	4	1
A	getOneTimePasswordLength()	0	4	1
A	getSecret()	0	7	2
A	getTimestamp()	0	4	1
A	getWindow()	0	7	2
A	makeTimestamp()	0	8	2
A	oathHotp()	0	13	2
A	getCurrentOtp()	0	8	1
A	setEnforceGoogleAuthenticatorCompatibility()	0	6	1
A	setKeyRegeneration()	0	4	1
A	setOneTimePasswordLength()	0	4	1
A	setSecret()	0	4	1
A	setWindow()	0	4	1
A	verify()	0	10	1
A	verifyKey()	0	15	2
A	findValidOTP()	0	13	4
A	verifyKeyNewer()	0	4	1
A	oathTruncate()	0	7	1
A	removeInvalidChars()	0	4	1
A	getKeyRegenerationTime()	0	4	1

<?php

namespace PragmaRX\Google2FA;

/*
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 *
 * PHP Google two-factor authentication module.
 *
 * See http://www.idontplaydarts.com/2011/07/google-totp-two-factor-authentication-for-php/
 * for more details
 *
 * @author Phil (Orginal author of this class)
 *
 * Changes have been made in the original class to remove all static methods and, also,
 * provide some other methods.
 *
 * @package    Google2FA
 * @author     Antonio Carlos Ribeiro @ PragmaRX
 **/

use PragmaRX\Google2FA\Support\Base32;
use PragmaRX\Google2FA\Support\QRCode;
use PragmaRX\Google2FA\Exceptions\InvalidCharactersException;
use PragmaRX\Google2FA\Exceptions\SecretKeyTooShortException;

class Google2FA
{
    use QRCode, Base32;

    /**
     * Characters valid for Base 32.
     */
    const VALID_FOR_B32 = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567';

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

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

    /**
     * Enforce Google Authenticator compatibility.
     */
    protected $enforceGoogleAuthenticatorCompatibility = true;

    /**
     * Secret.
     */
    protected $secret;

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

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

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

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

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

    /**
     * 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 $key     - Secret key in binary form.
     * @param int    $counter - Timestamp as returned by getTimestamp.
     *
     * @throws SecretKeyTooShortException
     *
     * @return string
     */
    public function oathHotp($key, $counter)
    {
        if (strlen($key) < 8) {
            throw new SecretKeyTooShortException();
        }

        // Counter must be 64-bit int
        $bin_counter = pack('N*', 0, $counter);

        $hash = hash_hmac('sha1', $bin_counter, $key, true);

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

    /**
     * Get the current one time password for a key.
     *
     * @param string $initalizationKey
     *
     * @throws InvalidCharactersException
     * @throws SecretKeyTooShortException
     *
     * @return string
     */
    public function getCurrentOtp($initalizationKey)
    {
        $timestamp = $this->getTimestamp();

        $secretKey = $this->base32Decode($initalizationKey);

        return $this->oathHotp($secretKey, $timestamp);
    }

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

        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 null|string $secret
     * @param null|int    $window
     * @param null|int    $timestamp
     * @param null|int    $oldTimestamp
     *
     * @return bool|int
     */
    public function verify($key, $secret = null, $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 null|int $window
     * @param null|int $timestamp
     * @param null|int $oldTimestamp
     *
     * @return bool|int
     */
    public function verifyKey($secret, $key, $window = null, $timestamp = null, $oldTimestamp = null)
    {
        $startingTimestamp = is_null($oldTimestamp)
            ? ($timestamp = $this->makeTimestamp($timestamp)) - $this->getWindow($window)
            : max($timestamp - $this->getWindow($window), $oldTimestamp);

        return $this->findValidOTP(
           $this->base32Decode($this->getSecret($secret)),
           $key,
           $window,
           $startingTimestamp,
           $timestamp,
           $oldTimestamp
       );
    }

    public function findValidOTP($binarySeed, $key, $window, $startingTimestamp, $timestamp, $oldTimestamp)
    {
        for (; $startingTimestamp <= $timestamp + $this->getWindow($window); $startingTimestamp++) {
            if (hash_equals($this->oathHotp($binarySeed, $startingTimestamp), $key)) {
                return
                    is_null($oldTimestamp)
                        ? true
                        : $startingTimestamp;
            }
        }

        return false;
    }

    /**
     * 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      $oldTimestamp - The timestamp from the last verified key
     * @param int|null $window
     * @param int|null $timestamp
     *
     * @return bool|int - false (not verified) or the timestamp of the verified key
     **/
    public function verifyKeyNewer($secret, $key, $oldTimestamp, $window = null, $timestamp = null)
    {
        return $this->verifyKey($secret, $key, $window, $timestamp, $oldTimestamp);
    }

    /**
     * Extracts the OTP from the SHA1 hash.
     *
     * @param string $hash
     *
     * @return int
     **/
    public function oathTruncate($hash)
    {
        $offset = ord($hash[19]) & 0xf;
        $temp = unpack('N', substr($hash, $offset, 4));

        return substr($temp[1] & 0x7fffffff, -$this->getOneTimePasswordLength());
    }

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

    /**
     * Get the key regeneration time in seconds.
     *
     * @return int
     */
    public function getKeyRegenerationTime()
    {
        return $this->keyRegeneration;
    }
}