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Show HN: Kong – Physical Cryptocurrency

kong.cash

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Re: Show HN: Kong – Physical Cryptocurrency

#151

Post by paulgerhardt »

dmitrygr wrote: post #26

This seems like a VERY cool technical solution in a desperate and fruitless search of a problem. > They consist of a flexible circuit board, specialized secure element chips and an independent NFC interface capable of powering the secure element. Each secure element stores an internally-generated ECDSA key pair that is associated with a unique smart contract on the Ethereum blockchain Who wants bills that cost $3 ea,…

Glad you think it's cool, given your background that comment means a lot to me personally.

I would contend it's not "in search of a problem" but trying to solve one. Specifically the usability nightmare that is cryptocurrency. Cash has tradeoffs but it has great usability properties. The space needs rebalancing in that direction.

Linen notes last about 4,000 bends before breaking, FPC lasts about 6,000. The stuff thats critical to validation is not in the 'bendy bit' pathway.

Did some ESD testing but the NFC chip bears most of the brunt here and not the secure element. Likewise the tiny holes dont bug me so much as the QF Packaging. Want to go slimmer in our next revision.

Re: Show HN: Kong – Physical Cryptocurrency

#152

Post by paulgerhardt »

WikipediasBad wrote: post #137

This is a fantastic project and great idea! One thing, I believe there are 2 hurdles to adoption: Kong - the unit of account/currency and Kong - the paper money. Don't you think you're trying to do 2 things at once? Why not try this unique technology with Dai or Tether which has a lot of traction? In fact, I would LOVE to have Dai bills.

We've discussed this. It was a bit lower risk to validate the hardware works with a new token than the additional complexity of Dai. A lot of other challenges there too but we're a small team.

Re: Show HN: Kong – Physical Cryptocurrency

#154

Post by dmitrygr »

paulgerhardt wrote: post #151
dmitrygr wrote: post #26

This seems like a VERY cool technical solution in a desperate and fruitless search of a problem. > They consist of a flexible circuit board, specialized secure element chips and an independent NFC interface capable of powering the secure element. Each secure element stores an internally-generated ECDSA key pair that is associated with a unique smart contract on the Ethereum blockchain Who wants bills that cost $3 ea,…

Glad you think it's cool, given your background that comment means a lot to me personally. I would contend it's not "in search of a problem" but trying to solve one. Specifically the usability nightmare that is cryptocurrency. Cash has tradeoffs but it has great usability properties. The space needs rebalancing in that direction. Linen notes last about 4,000 bends before breaking, FPC lasts about 6,000. The stuff tha…

> the usability nightmare that is cryptocurrency

yup. with you so far

> FPC lasts about 6,000

But, how tests are done differs from what bills face: Large curve radius, slow curving, nothing sharp poking at it in the middle. Basically the opposite of what is going on in tight pockets/purses.

> NFC chip bears most of the brunt here and not the secure element.

Unless the dielectric over your secure element is some previously unknown type, a few kilovolts will arc right through it and hit your secure element.

Re: Show HN: Kong – Physical Cryptocurrency

#155

Post by rglullis »

aazaa wrote: post #49

I really like the concept of physical electronic cash, but in practice nobody has figured out how to make it work. There are many attacks to consider. The most obvious is to obtain the private key. If you did so, you could give the note to someone else in an environment lacking network access. This would enable double-spending - the main problem Bitcoin solves. The attack can range in complexity from breaking into th…

I haven't read the paper (yet), but from I read down-thread Kong is keeping reserves for the notes which can be redeemed later.

Wouldn't this mean that if the notes are destroyed the value of the other notes would increase?

Re: Show HN: Kong – Physical Cryptocurrency

#156

Post by paulgerhardt »

skosch wrote: post #93

Can you comment on the history of the name, printed as 港 on the bills? For those unaware, the character means "harbour"; it's the Kong in Hong Kong – is there any relationship to the HKD?

Context: https://news.ycombinator.com/item?id=21758004

Re: Show HN: Kong – Physical Cryptocurrency

#157

Post by asdf21 »

ilaksh wrote: post #77
nostromo wrote: post #63

One of the best things about Bitcoin is that it’s not physical. If you want a physical currency that can’t be printed, use gold bullion.

Maybe silver? I mean even a tiny 1/10 oz gold coin is worth $140

You also can't tell if gold is real or gold plated, etc.

Re: Show HN: Kong – Physical Cryptocurrency

#159

Post by zelly »

paulgerhardt wrote: post #79
zelly wrote: post #72

IMO this breaks the entire security model of cryptocurrency. If these bills are intended to be spent hand-to-hand in meatspace without cryptographic validation on a computer, then it is no longer a cryptocurrency. It is another paper currency like the U.S. Treasury's. The innovation of Bitcoin was money as a purely digital artifact that cannot be double spent. As a merchant accepting Kong bucks, I have no idea how ma…

The bills are intended to be spent hand-to-hand in meatspace with cryptographic validation. See section 2.1 [1] The innovation of Bitcoin was decentralized electronic peer-to-peer cash. Kong does not remove any of those elements and makes the overhead of the peer-to-peer bit easier. Physical cash is still the dominant form of payment. The advancement here is figuring out how to issue physical cash without needing a c…

> The bills are intended to be spent hand-to-hand in meatspace with cryptographic validation. See section 2.1 [1]

When I accept a physical note, do bits move on the Ethereum blockchain? If not, how do I know that it's really mine?

This reminds me of when people sold Bitcoin private keys ("paper wallets") on eBay. I've heard some people do OTC trades by swapping private keys when they don't want the transaction recorded, but I assume these people know each other well. You save money on miner fees and gain some privacy, but you sacrifice trustlessness.

Re: Show HN: Kong – Physical Cryptocurrency

#160

Post by drudu »

krick wrote: post #62

I don't get it. Is it some sort of concept art? What's the point? Sure, it can be used as money (assuming what authors say is correct). Virtually any physical items that are hard to fake can be used as money, as long as people believe it's worth something. And if we are okay with complicated and rather expensive manufacturing process (since Kong isn't something you find in the forest), it really is a non-problem to c…

You got it - these are an excellent way to buy cocaine. Absolutely worthless (to a petty thief) and useful for buying drugs. Love it.
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