Secret Knock Detecting door lock

Have some spare time on your hands for a DIY project? The Secret Knock Detecting door lock might be your cup of tea, where it relies on an Arduino alongside a ragtag collection of parts from a lab. The end result is a device that unlocks your door whenever it “hears” the right knock pattern which only you are privy to (alongside other people who you’ve shared to answer with). Sorta like a big boys’ secret handshake, albeit much cooler. Of course, this doesn’t counter who ever is eavesdropping on the pattern of your knock in order to gain access later on though. Any workarounds you can think of?