Re: Virtual currency without block chain

Quote from: HunterMinerCrafter on October 04, 2014, 07:58:10 AM

Quote from: Anders on October 04, 2014, 05:50:10 AM

The double spending problem is completely eliminated by having unique coin IDs and using digital signatures. The worst attack nodes could do would be to mess up the distributed hash table.

If you can "mess up" the DHT then you can double spend. For example, send some coins to an exchange, trade them for btc, then scrub the transaction from the dht (perhaps via Sybil attack) and send the same coins off to some second exchange and sell them again. Having the coins identified and signed doesn't really help the first exchange.

You can't replace transactions. The unique ID for a coin makes it stored as a single value. By messing up I mean that an attacker can put wrong information into the DHT or delete information. If the attacker manages to delete a coin and then tries to put it in again with another owner then the digital signature would have to be cracked for that to be a successful attack.

I see what you mean now. There is no complete history for the transactions so an attacker can simply make up a transaction and sign it correctly. Yes, then messing up the DHT can lead to double spend.