Google authenticator

, _(*1)

Supports one-time passwords accordings (HOTP & TOTP) according to RFC 4226 and RFC 6238., _(*2)

Working with one-time passwords

The following shows the API for time-based one-time passwords (TOTP):, _(*3)

use com\google\authenticator\{TimeBased, Tolerance};
use util\Secret;

$secret= new Secret('2BX6RYQ4MD5M46KP');
$timebased= new TimeBased($secret);
$time= time();

// Get token for a given time
$token= $timebased->at($time);
$token= $timebased->current();

// Must match exactly
$verified= $timebased->verify($token, $time, Tolerance::$NONE);

// Allows previous and next
$verified= $timebased->verify($token);
$verified= $timebased->verify($token, $time);
$verified= $timebased->verify($token, $time, Tolerance::$PREVIOUS_AND_NEXT);

The following shows the API for counter-based one-time passwords (HOTP):, _(*4)

use com\google\authenticator\{CounterBased, Tolerance};
use util\Secret;

$secret= new Secret('2BX6RYQ4MD5M46KP');
$counterbased= new CounterBased($secret);
$counter= 0;

// Get token for a given counter
$token= $counterbased->at($counter);

// Must match exactly
$verified= $counterbased->verify($token, $counter, Tolerance::$NONE);

// Allows previous and next
$verified= $counterbased->verify($token, $counter);
$verified= $counterbased->verify($token, $counter, Tolerance::$PREVIOUS_AND_NEXT);

Note: We use util.Secret so that in case of exceptions, the secret will not appear in stack traces., _(*5)

Creating secrets

As an issuer of OTPs, you need to create random secrets in order to seed both client and server. Using the provisioningUri() method, you can fetch the URIs used to configure the clients., _(*6)

use com\google\authenticator\{CounterBased, TimeBased, Secrets};

$random= Secrets::random();

// HOTP, otpauth://hotp/{account}?secret={secret}&counter={counter}
$counterbased= new CounterBased($random);
$uri= $counterbased->provisioningUri($account);             // Start with counter= 0
$uri= $counterbased->provisioningUri($account, $initial);   // Start with counter= $initial

// TOTP, otpauth://totp/{account}?secret={secret}
$timebased= new TimeBased($random);
$uri= $timebased->provisioningUri($account);

// Pass a map of string to append additional parameters
$uri= $timebased->provisioningUri($account, ['issuer' => 'ACME Co']);

// Pass an array to namespace the account, yields "ACME%20Co:user@example.com"
$uri= $timebased->provisioningUri(['ACME Co', 'user@example.com']);