welsonjs/app/assets/php/class.tfa.php

62 lines
1.4 KiB
PHP

<?php
// https://github.com/dimamedia/PHP-Simple-TOTP-and-PubKey
class tfa {
// RFC4648 Base32 alphabet
private $alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567";
function getOtp($key) {
/* Base32 decoder */
// Remove spaces from the given public key and converting to an array
$key = str_split(str_replace(" ","",$key));
$n = 0;
$j = 0;
$binary_key = "";
// Decode public key's each character to base32 and save into binary chunks
foreach($key as $char) {
$n = $n << 5;
$n = $n + stripos($this->alphabet, $char);
$j += 5;
if($j >= 8) {
$j -= 8;
$binary_key .= chr(($n & (0xFF << $j)) >> $j);
}
}
/* End of Base32 decoder */
// current unix time 30sec period as binary
$binary_timestamp = pack('N*', 0) . pack('N*', floor(microtime(true)/30));
// generate keyed hash
$hash = hash_hmac('sha1', $binary_timestamp, $binary_key, true);
// generate otp from hash
$offset = ord($hash[19]) & 0xf;
$otp = (
((ord($hash[$offset+0]) & 0x7f) << 24 ) |
((ord($hash[$offset+1]) & 0xff) << 16 ) |
((ord($hash[$offset+2]) & 0xff) << 8 ) |
(ord($hash[$offset+3]) & 0xff)
) % pow(10, 6);
return $otp;
}
function getPubKey() {
$alphabet = str_split($this->alphabet);
$key = '';
// generate 16 chars public key from Base32 alphabet
for ($i = 0; $i < 16; $i++) $key .= $alphabet[mt_rand(0,31)];
// split into 4x4 chunks for easy reading
return implode(" ", str_split($key, 4));
}
}
?>