phpc#
<code>public static function oath_hotp($key, $counter){ $bin_counter = pack('N*', 0) . pack('N*', $counter); // Counter must be 64-bit int $hash = hash_hmac ('sha1', $bin_counter, $key, true); return str_pad(self::oath_truncate($hash), self::otpLength, '0', STR_PAD_LEFT);}public static function oath_truncate($hash){ $offset = ord($hash[19]) & 0xf; return ( ((ord($hash[$offset+0]) & 0x7f) </code>self::otpLength是类中的一个变量
