Quote from: Mike Hearn on January 23, 2014, 11:44:03 PM

This idea is useful because most people have one (or maybe two/three) passports

Ummm, no, Mike, they don't.

"Of the 308 million-plus citizens in the United States, 30% have passports." (CNN)

I couldn't find stats on the whole world because Google, Yahoo and Bing only returned stats on Americans for some reason. But, I have a hard time imagining it being higher in third-world countries.

Quote from: Mike Hearn on January 23, 2014, 11:44:03 PM

Quote

I think he way is out of line, trying to force everybody to proof their identity by verifying their passport.

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So, I suggest a second line of research - use some very advanced and modern mathematics to create a mathematical proof that you possess a passport (the government issued kind) without revealing any information from it.
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I get what you're trying to do, Mike. You want to somehow speed up the validation of anonymous transactions. But, trying to include ANY aspect of identity to validate an anonymous transaction is, as others on this thread have suggested, a very bad idea from the start.

Let's pretend like everyone in the world has a passport. One very big issue today with RFID is how EASY it is to STEAL the info on the passport you're presuming isn't stolen. If your protocol extension ever became popular, you'd just give passport info thieves yet another reason to copy that info. Honest people may not have more than a couple of passports. But, dishonest people can have thousands of copies of passports of honest people without anyone knowing they have the copies. And dishonest government organizations or people?!?

Let's set aside anonymity for a moment. Isn't this a very round about way to try to verify that a transaction is valid? You use the man-in-the-middle attack analogy, which is usually used for plain texting a cipher. What the man-in-the-middle attack relies on with SSL is that only one side is providing a certificate. This attack fails when BOTH sides provide a certificate, and both sides validate the other side.

While I hate using this SSL analogy at all in the discussion of verifying Bitcoin transactions, because it is not even close to being the same thing, the bottom line is you can mathematically verify communications in a way that prevents a man-in-the-middle attack. Bitcoin is in a position to offer that, unlike SSL. SSL doesn't because of convenience, and because it ultimately relies on identity and third parties in the HTTP world, which, ironically, have made SSL expensive for non-revenue generating entities -- like people. That is, it is expensive to purchase a cert that can be validated by a "trusted" third-party.

But, I digress. In Bitcoin, you can prevent a man-in-the-middle without resorting to a broken identity third-party based barely trustable system like SSL over HTTP.

So, beginning any transaction integrity validation scheme with public identity to increase trust, knowable or non-knowable, just opens a huge can of worms and increases the risk to the Bitcoin network and its users rather than lowering it.