This tool with generate a daily password that reset the Dahua master password. You just need to run the password generator and enter the actual DVR date to get a new password (the date you see on the screen). However, this method works for older Dahua DVRs/NVRs, it no longer works on the new Dahua recorders since they run a revamped firmware. If you lost the admin password for an old Dahua DVR you can use a password generator to reset it. Read this article for other methods on how to reset the master/admin password for Dahua recorders.
Download the Dahua daily password generator on this link (google drive link).