3 ms·
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
by aazaa 7y ago
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 the secure element to physically separating the element from the note. The latter approach was used way back to pull private keys from Casascius coins by dissolving the adhesive on the security sticker.
I suspect not all of these kinds of attacks have been considered by the creators.
If it becomes necessary to verify Kong with a network connection, the main value proposition disappears. That can be done already without a physical note.
- paulgerhardt 7y agoWe have considered both of those attacks and address them in section 2.2 and 3.2 of the white paper respectively[1]. The short version is the key extraction attacks on this specific hardened chip are more expensive than the value they escrow, and in the event a key was extracted it creates a race condition at the period of claim not during the lifetime of its use - still providing some utility. What Kong does that Casascius didn't is provide guarantees that the minter never saw the private key. [1] https://ipfs.io/ipfs/QmRNRCocj4PwKMXrd1jeUGw7ASQSuEk7BDJu5KsGuWBXAX https://ipfs.io/ipfs/QmRNRCocj4PwKMXrd1jeUGw7ASQSuEk7BDJu5Ks...
- melcor 7y ago> in the event a key was extracted it creates a race condition at the period of claim not during the lifetime of its use - still providing some utility. So say the key was extracted, you would not be aware until the "maturity" or whatever time you can claim the real value? How would one then know and trust that the note I'm holding on to won't be claimed by someone else at the period of claim? As far as I see it my best option would be to try and offload any Kong in my possession as soon as possible for real goods or other currency.
- rglullis 7y agoI 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?
- bananabreakfast 7y agoWhy would you suspect they haven't thought of simple attacks like these^? You haven't even read their paper and are already jumping to conclusions