<?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
);
}
}