Is this statement True or False about Bitcoin

[mikewillz]

I won't say who via twitter but a #Hacker, #engineer, #entrepreneur. #Consultant had this to say

"You could shut Bitcoin down with a DDoS that would cost under $1 million to execute."

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[mewantsbitcoins]

You can ddos specific nodes, but they will never be able to ddos all.
If I want to send you some bitcoins, I just connect to you(assuming our blockchains are up to date) and can execute the transaction.

[Anonymous]

Absolutely, most certainly false.

[mikewillz]

I'm lost without you guys I swear 

[fabianhjr]

It is false, you can take torrents as an example + the streisand effect.

[TheVirus]

It depends if they found a flaw in the network itself. Hitting Bitcoin with standard DDoS tactics will do nothing, but if they found a flaw in the way the users connect to one another and know of a way to have the users 'unknowingly' DDoS each other, then yes, it can happen. I haven't looked at the Bitcoin protocol so I can't really comment on it, but it wouldn't be surprising if something like this does exist. Think of it like the way SYN floods used to work:

User1: SYN -> User2
User2: SYNACK -> User3<fake>
User1: SYN -> User2
User2: SYNACK -> User3<fake>
...

If a certain flaw were found, it is theoretically possible to have the network flood itself once it is seeded in some specific way.

[ene]

$1 million can buy enough mining hardware to take over the bitcoin network and basically ruin it for everybody. Assuming you can even find that many GPUs, which you won't on the open market.

You would need about 3,500 mining rigs, each with 3x6990 AMD cards. I haven't done the maths, but you can probably buy that for $1 million. Edit: More like $5 million.

That's not technically a DDoS attack though.

[zamarok]

$1 million can buy enough mining hardware to take over the bitcoin network and basically ruin it for everybody. Assuming you can even find that many GPUs, which you won't on the open market.

You would need about 3,500 mining rigs, each with 3x6990 AMD cards. I haven't done the maths, but you can probably buy that for $1 million. Edit: More like $5 million.

That's not technically a DDoS attack though.

When you buy large quantities for lots of money, you usually get a discount. You could negotiate a contract with Sapphire, and have them make you a bunch of your desired GPU for cheaper than retail price.

[fabianhjr]

Trippy, your calculations are flawed.

The current estimated hashing power is near the 7.5 thps mark. A 5970/6990 can pull around 0.8 ghps. Dividing yields an estimate of 9375 5970s/6990s. They both hover in the 700 USD mark so it will take near 6.5 Million in hashing hardware just to reach parity with the network. Keep in mind this does not include the facility/datacenter and specific required hardware like PSUs, Motherboards, CPUs, on-site admin, cooling(For such a big density). That would topple the cost to well over the 15 Million mark plus a 50K USD per month maintenance + bills.

This would not only stop being enough after a week or two seeing its current growth, it would be worthless for a while. :/ I mean, you got the coins, then what? If you expect to get at least some of it back, you would sell as any other miner and you would end up being assimilated by the network. This thing will reach the 50 Million quite soon, in about 2 weeks or so. There is no sense in trying.

zamrock, still really expensive, though a real possibility. Why don't we miners seek for a huge wholesale deal?

[minerX]

I won't say who via twitter but a #Hacker, #engineer, #entrepreneur. #Consultant had this to say

"You could shut Bitcoin down with a DDoS that would cost under $1 million to execute."

Laughable.  Who are they going to attack?  The pools?  And then what.... Everybody switches to a different pool or solo mines.  Then they plan on attacking everyone separately?

Not to mention hackers are generally poor bastards.  No the demise of bitcoin will not be through hackers.  It will be through the U.S. Government calling it illegal.

[ene]

Yes they were flawed, it was only a back-of-the-envelope calculation. I didn't think the maintenance cost and building cost would be so expensive compared to the GPUs themselves, but you probably know better.

I think you may have misunderstood my line of attack though. Once somebody has more computing power than everybody else put together, they should go about 1,000 blocks back and try to build a new chain building off that, in secret. (This would take a week.) However their chain will not include any of the transactions from the last 1,000 legitimate blocks. Once it becomes longer than the existing chain, they publish it and instantaneously a whole week of transactions un-happen, i.e. they are reversed and the money (including mining fees) returns to the hands of the original owner, whereas the 50,000 BTC legitimately mined disappear, and the new 50,000 BTC generated are owned by one bitcoin address, the attacker's.

This would cause a massive panic and the price of BTC would crash on the exchanges.

They are then pretty much done in my opinion. They can turn off their datacentre and as long as everybody knows that the datacentre is there and can be powered up again at any time, people will not want to use bitcoins or any similar system.

Of course ideally all the miners would rally together and increase the network power, so much so that our attacker is forced to order another batch of GPUs or give up. But that's a little too idealistic for me.

[fabianhjr]

I am just pointing out the fact that even if they would be able to do so they are literally trashing a lot of money. We are about to experience a lot of difficulty jumps each time making it harder to stop.

When BTC is being traded at 100 USD the likely cost for this project would be of 75 Million USD and the constant ups in price and difficulty will keep it rising, you can't simply wait to get a week of progress, in that week the network will overrun you.

[jerfelix]

Yes they were flawed, it was only a back-of-the-envelope calculation. I didn't think the maintenance cost and building cost would be so expensive compared to the GPUs themselves, but you probably know better.

I think you may have misunderstood my line of attack though. Once somebody has more computing power than everybody else put together, they should go about 1,000 blocks back and try to build a new chain building off that, in secret. (This would take a week.) However their chain will not include any of the transactions from the last 1,000 legitimate blocks. Once it becomes longer than the existing chain, they publish it and instantaneously a whole week of transactions un-happen, i.e. they are reversed and the money (including mining fees) returns to the hands of the original owner, whereas the 50,000 BTC legitimately mined disappear, and the new 50,000 BTC generated are owned by one bitcoin address, the attacker's.

This would cause a massive panic and the price of BTC would crash on the exchanges.

They are then pretty much done in my opinion. They can turn off their datacentre and as long as everybody knows that the datacentre is there and can be powered up again at any time, people will not want to use bitcoins or any similar system.

Of course ideally all the miners would rally together and increase the network power, so much so that our attacker is forced to order another batch of GPUs or give up. But that's a little too idealistic for me.

So in this scenario, they will have spent a massive amount of money on computing power.  And it has to be FAR greater than the current combined network (to create fake week-old transactions, and to catch up to present, and then finally to surpass the present).  And then, according to your scenario, they will create their own 50,000 BTC (which, at current market prices is itself worth almost $1M), and then throw away that $1M, by driving the price of BTC to zero.

Who would do this?  A government, I suppose.  But you wouldn't do it to make money!

[Sukrim]

I won't say who via twitter but a #Hacker, #engineer, #entrepreneur. #Consultant had this to say

"You could shut Bitcoin down with a DDoS that would cost under $1 million to execute."

I would rephrase it to:

"You could severely disrupt Bitcoin with a DDoS that would cost under $1 million to execute."

Reasons/Targets:
Attacking main pools + the IRC channel as single point of failure would make transactions VERY slow to process. Once 3-4 big pools are down, it takes ~1 hour to mine 1 block + the miners WON'T solo mine but try to switch to other pools (if even) effectively DDOSing these to death too. Miners are more like sheep, they seem to like to be in herds!

As a result the exchange rate on MtGox would plummet, if some more alert miners cash out, then skyrocket again if some investors have any money lying around. Chaos + Confusion will break out.

I think you will cause a nice weekend and a deep dent in the global hashrate with this, in the end it won#t bring Bitcoin down though, and might very likely even lead to more popularity of BTC than before (if it is really a big attack, not just a DOS attempt at 1 single pool). It might however shatter trust a bit, making people more alert with what they are doing with their money...

[IIOII]

...
Who would do this?  A government, I suppose.  But you wouldn't do it to make money!

Does this make it less threatening?

Bitcoin opposes state authority - therefore it is not unlikely to happen.

[joan]

He might have been referring to the penny-flood type of attack.
Or creating ultra big transactions by sending massive ammount of coins to yourself split in a high number of different addresses/clients. The attack funding would actually be spent on fees. If they can craft transactions that are really heavy, that could obstruct the network for a while ?

[jerfelix]

Does this make it less threatening?

Yes.  The fewer entities that have motivation to do it, the less threatening it is.

[Mike Hearn]

You could (temporarily) DoS all of Bitcoin for far less money than a million dollars. However, DoS attacks are illegal, doubly so if you use a botnet to get lots of IPs and anonymize your tracks.

If somebody does actually start DoSing Bitcoin, I guess it'd be time to add autodrop code that would detect and block bad IPs. The attack could be quite disruptive until people upgraded to the new version.

[MoonShadow]

I won't say who via twitter but a #Hacker, #engineer, #entrepreneur. #Consultant had this to say

"You could shut Bitcoin down with a DDoS that would cost under $1 million to execute."

That statement is not true.  A DDOS attack would, at worst, prevent the network from normal function while the attack was ongoing.  It couldn't do any lasting harm to the currency system or the network, a non-trivial portion of which does not exist in any "publicly" accessible form that can be dossed at all.

[MoonShadow]

If they can craft transactions that are really heavy, that could obstruct the network for a while ?

Yes, but then the miners would be laughing at the attacker, because he would have to be paying them for the privilage of attacking the network.  This kind of attack ends once the money runs dry.