 Yeah, hi, I Sometimes pretend to be a cryptographer, but at the moment I'm involved in a startup that's doing data mining for real estate. It's called Deckard and What we do is we find out interesting stuff about people and their properties and we sell it to the government Now by way of anecdote governments are not smart So here's here's the anecdote. Okay, so back in the 1970s 7400 series TTL proves I'm old we the Australian government put out a tender for these chips and of course all of the chips at the time were produced in the US except Japan was trying to get in the game and Japan put in a tender that was much much much cheaper than the Australian that sorry than the US people and They won the tender and when the chips arrived We it had a note. We don't know why you specified 5% defective chips, but we packaged them separately for your convenience so Recently Recently we had the same kind of interaction with I'll just drop a hint here that I live in San Diego And it was probably my local county we're tendering to give data to the government and They had they said oh, no, you can't just have a contract you have to go through the tender process the RFQ process So they put out an RFQ But the only template they had for think for an RFQ was things like light bulbs or office chairs or whatever and and it says give us 250 and We will choose 50 at random and test them and give you back the other 200 You know, this is just what they do stuff like this Except of course, we're selling them data and we can't give them 250 and then take back the 200 that they've already seen So of course I came up with the trivial Zero knowledge proof basically given them a spreadsheet with slightly obfuscated addresses and a nonce and a hash and It's essentially a really cheap and nasty zero knowledge proof that there's no duplicates that it really is You know that when you chose the particular sequence number that that's the one you ended up getting It all sort of worked So you have to seed the hashes with different nonces so that you know You can't just do a trivial address matching thing because there's only a million properties in San Diego And you know the addresses of all of them if they do they're the county So you know pretty obvious and We only included the partial addresses because we wanted to convince them that you know that they really did got get what they asked for So I thought this was pretty cool. It took me nearly 10 minutes to think of it I was describing it to Nadia. Of course it took her. No actually wasn't Nadia is Christine It's what I was describing it to Christine It took her maybe 30 seconds to tell me what the answer was. I mean, you know came came up with the same solution So, you know But of course that wasn't what they wanted to do What they wanted to do was sit beside somebody with a spreadsheet on the screen and point and They would accept the fact that what we emailed to them was what they pointed out on the screen so That was it Thank you very trivial