if they are running a modified bitcoind than I would start to worry about my BTC's
Why? Stop spreading FUD, thank you.
Hi Gabi
First at all I am not spreadding FUD s all over the place I just dont want a good idea beeing destroyed because all in a sudden someone realized there is a weak spot in the bitcoind which someone forgotten to mention and one morning the network is not working anymore because of this!
Second WHY?
If you look at a earlyer post of mine called "Bitcoin transactions and fatty acids" it says there:
Is there a way to bring down or slow down the Bitcoin network by producing very long transactions by sending small ammounts of BTC from one client to another one or even set up a botnet to send transactions to make them longer so that in the long run the network will be clocked up like a person who had to many long chained fatty acids to eat his whole life and suddenly dies because his arteries are clogged up.
For example with the
sendmany <fromaccount> {address:amount,...} [minconf=1] [comment]
command and some script?
Kjj replied:
It would be expensive to do this.
The network uses a calculation called priority to decide if it should relay your transaction without requiring a fee. The basic idea is that a simple transaction takes about 250 bytes, and "1 BTC that is 1 day old" is a good rule of thumb. So, we look at each of your inputs and calculate the amount in BTC times the number of confirmations, and add those up. Then we divide by the size of the total transaction, and if the ratio of BTC-days to bytes is worse than 1:250, we don't relay it until it has aged enough to make that ratio true.* The standard behavior for mining is then to do the same calculation to decide if that transaction should be included in the next block candidate created. **
So, if you are redeeming a 1 BTC input that has 1500 confirmations, most of the network will accept it with no fee up to about 2500 bytes, (very) roughly 10 outputs. But then each of those outputs will be 0.1 BTC, and you won't be able to send them for free until 10 more days have passed. If you need to move them faster, you can do so, but not for free, you need to include a fee in your transaction.
Spamming the network in this way very quickly becomes too costly to do.
* nodes running different software, or that have been modified, will do this differently. Some nodes relay everything on principle.
** nodes running different software, or that have been modified, will do this differently. Some nodes mine
So my point is: If blockchain.info running modified clients or bitcoind's they also should be able to alter a client in such a way that one can undermine the "priority to decide" and use it to jam the network.
So my rough guess is with 10000 BTC you could get some professionals which are able to alter the client and get the whole network down over a period of some time.
OR NOT ?