Copyright (c) 2014 Robin Leffmann
TOTP is a simple, compact and bare-bones PHP class for calculating TOTP tokens, commonly used for two-factor authentication with mobile apps. It comprises three public functions of which only one is necessary to call to get a token.
Simply call TOTP::getOTP( $secret [, $digits = 6 [, $period = 30 [, $offset = 0 [, $algo = 'sha1' ]]]] ) which returns an array with the key otp holding the authentication token, or the key err describing an eventual error.
The other two functions are meant to be convenient utilities:
TOTP::genSecret( [ $length = 24 ] ) generates a TOTP-compatible pseudorandom secret in Base32 ASCII, returning an array with the key secret holding the random secret or the key err describing an eventual error.
TOTP::genURI( $account, $secret [, $digits = null [, $period = null [, $issuer = null [, $algo = null ]]]] ) returns an array with the key uri holding an otpauth:// style URI providing the supplied parameters, which can e.g. be embedded in a QR code image, or the key err describing an eventual error.
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TOTP is released under the Creative Commons BY-NC-SA 4.0 license: http://creativecommons.org/licenses/by-nc-sa/4.0/