Such a system is not “decentralized”, but more like a “replicated center” system, as there is an absolute necessity to gather all the existing data in a single point to make any meaningful operation. Partial knowledge does not work. The authors describe those full nodes as “super-peers” saying that
No. The system is decentralized in that the latest produced block is verified by every node by computing the hash themselves with the received nonce. It get exponentially harder to try and modify transactions that are deeper in the block chain. The concept of decentralization is that no node accepts any new data from the network as a given. It will verify the hash and react independently of other nodes. Previously network wide accepted blocks are considered valid by default since the computing power needed to change them quickly becomes astronomical.
Partial knowledge can easily work. Only propagate up to the last back up block to the light weight clients.
Thus, Bitcoin is only “peer-to-peer” in the sense of the British Peerage system. Bitcoin “commoners” must appeal to their “lords” who have sufficient means to judge on validity of transactions and to seal those transactions as valid, likely for a fee.
Once again no, each client reacts independently to the data newly propagated. Data deeper in the block chain is valid by that same process.
Thus, for perfect anonymity, both sender and receiver have to split every complex transaction among separate pairs of throw-away identities. But at this point, transactions stop being technically atomic, in addition to the fact that the system becomes quite complicated and heavyweight.
Yeah like someone obsessed with anonymity won't come up with an automated software to do that... There's barely any extra weight on the system. Block hashing is independent of transaction size. The space required to store those extra bits of data is perfectly in line with the network capitalization.
There are transaction fees. Those who truly want to become anonymous by splitting down their transactions have to pay higher fees. It is only fair and sensible.
those “honest” nodes need to burn maximum amounts of energy continuously, round the clock, 24x365, just to keep the system afloat. Not green at all!
Silly argument proven wrong 20 times over. Move on, nothing to see.
Meanwhile, an attacker may only mobilize his CPU power temporarily to carry out his deeds.
I'd like to understand who would bother buying up 50% of the network hashrate, getting that steady BTC daily reward, to then shoot himself in the foot by forking the chain in order to "make a profit out of double spending". That's nonsensical. The system is built so that rewards for trying to cheat the system provide less return than simply contributing to it.
The only valid motive for an attack on Bitcoin is to outright hurt or attempt to take down the system. The defense against that is that the network is maintained by mining, and as it grows mining gets more profitable, effectively increasing by leaps and bounds the amount of wealth a single individual has to invest to take it over. That's like one guy trying to stop the rest of the planet from switching to gold. As the group of adopters is small, he can bully it with an AK. But that's the only time he can hope to attack it. By the time Bitcoin gets big enough that haters will want to target, it'll take them the equivalent of an H bomb to do it on their own. Of course if the whole government wants to go after Bitcoin, that's another story. But still I'd like to understand how people can use gold if the gov sends out the military to kill on sight whoever uses it.
Meanwhile, his victims need either to check the full transaction history and all the pending transactions (in the world), and/or wait sufficient time (10 min to 1 hour) till the transaction in question is reliably settled in the transaction history.
Yeah while you shit your pants hoping that guy who payed you with his credit card isn't going to charge you back in the span of the whole WEEK after the payment. Gimme a break.
Potentially, a CPU-rich well-connected peer may delay his newly created block till a competing block is received
Not exactly. The block header is built off of the hash of the previous block. For that attack to work you need to propagate that "held" block from the opposite end of the network.
A sufficiently CPU-rich attacker may perpetuate this tie indefinitely, potentially making the network to flip-flop between two branches of transaction history, with somewhat unclear consequences. Such a process will create side effects of mass transaction rollbacks, implicit status changes of pending transactions and coin creation/disappearance.
Coins don't disappear, period. The fact that the network maintains the fork until one of the branches is proven valid is so that no valid transaction is lost. If the attacker includes fake transactions, those will go away as the block is turned down by the network. He can mix up those with some valid transactions to have these bounced back too, sure. What we are looking at here is a huge amount of dedicated power for the sole purpose of being a b**** to the network. The only effect will be to slow down the network.
As you might see, the claims laid by Bitcoin are far from definite. In terms of peertopeerness, privacy, security and usability it might actually turn worse than the present-day real-world legacy banking system. Here and now (Netherlands, 2011) I enjoy an instant, secure, privacy-preserving payment system which charges no fees for domestic transfers
BitTorrent is technologically complicated, infrastructure-wise inefficient, much less usable than a regular Web download, etc.
How many http servers do you know with terabytes worth of copyright infringing content on it that is free to access anywhere in the world while providing top speed to all its users? Please name one... And despite all the efforts of the music, movie, gaming industry AND the US government, BitTorrent is still out there, working flawlessly.
Also, where's the DoS argument in this piece?