Hmm, maybe.

Care to make a wager?

As I mentioned above, when a node sees a new transaction, it checks that transaction for validity, including making sure that it has not already seen a transaction that spends those same coins.  The second transaction thus fails the validity check and is not propogated furthur.  So, in the end, the first transaction to hit the p2p network will get propogate to the majority of the peer nodes, and stop when it hits the propogation wave of the second transaction.  The differences between the first and second transaction would be milliseconds, and it would likely take less than three seconds for any other conflicting transactions to fail right at the vending machine server itself.  A vending machine server would also have an economic encentive to maintain a connection with a major miner, such as a pool, due to the lopsided propogation that such a peer connection provides.  So, even with a 10 second window, only those who hit send right at the beginning of the window will succeed, and players also have an encentive to cheat by sending early.  Maybe a few people could get the machine to give up some loot, but one of them is actually going to still get paid.  The vast majority of players are going to get nothing.

Well, no.  It wouldn't.  What the nodes actually do is announce the hash value of transactions that it is aware of to nodes, and nodes that do not have that transaction will request it.  If that node considers it valid, it also then annouces to it's other peers.  So what would have to happen is that the vending machine would have to pick a couple of it's peers out to not announce that transaction to, so that it could just wait to get that transaction to announce it back to itself, thus confirming that said transaction has moved across the p2p (that said vending machine could see) without another conflicting transaction hitting the chosen peers first.  I oversimplified the scenario, I guess.  Most people seem to get very confused.

This is not true at all.  Communism does require a near absolute participation rate to be successful, but libertarianism does not.  You seem to believe that, because we have an ideal goal to aim for, that a society that fails to obtain such lofty heights wouldn't still be a society that we would prefer to live in right now.  That is a rediculous assumption.  We aim high, in part, because that is the only way to make progress.  For if you start with the open willingness to compromise, you will end up settling for less than you could have achieved.  This is true in any negotiation, and politics is basicly a negotiation on an ongoing and national scale.  Would a communist prefer to live in a moderately more socially dictated society that ours?  Probably not, because a thinking communist would understand that a half-measure of communism would undermine itself.  This is not so with liberty.  I would choose a somewhat more libertarian society, and if others were to choose to create small enclaves of communism within that society, that effects me very little if at all.

There are a number of ways to reduce the risks in accepting a transaction as proof of payment within bitcoin.  Waiting for confirmations is, obviously, the most secure and trustworthy method, and the only one presently established.  However, there are a couple of ways that a vendor rapidly selling low value items in meatspace can significantly reduce their exposure to just such a coordinated fraud.  First off, ten seconds is pretty tight timing, so it's not going to be an easy attack anyway. 

But think of it like this...

Vending machine doesn't do the verifications itself, this would likely be done at the owning company's server, but for simplicity let us imagine that it's done at the vending machine.

One participating attacker walks up to vending machine, no one waiting.  His watch is set for just the right time to send the final transaction.  So he chooses his loot and sets up the transaction, hears his watch alarm and presses 'send'.

The transaction hits the p2p network, doesn't matter if the attacker sent it to the vending machine first or directly to the Internet.  Vending machine is waiting a few seconds for the transaction to move across the p2p network.  What it is waiting for is to see all of it's peers, and most importantly it's most 'netgraphicly' distant peers, to tell it about the new transaction.  If all of it's peers tell it that this transaction exists, then that means that transaction is the first one that spends those coins that said peer has seen.  It also means that those peers will ignore any other transactions that spend those same coins, refusing to include them in mining blocks or forward them to their own peers.  So if the vending machine sees that all of it's peers have received and accepted that transaction as valid, then that means that vending machine was the first to get it's transaction out onto the p2p network, and thus it doesn't much care about any other transactions because it's astronomically unlikely that a double spend attempt will work out counter to it's own favor.

However, if even one peer does not tell the vending machine about the new transaction within a set period of time, then that likely means that said peer has already seen a conflicting transaction, and the vending machine simply refuses to dispense.

Do you really think so?  I download files larger than that via bittorrent for a few hours entertainment.

Interesting analysis.  Can't say that I would agree with your premises, though.

Only because the developers haven't gotten there yet.  Really, we want different clients to fork out and handle security in different ways.  We definately don't want a monolithic approach to security with bitcoin.  Which is one reason why the wallet.dat file isn't encrypted natively to begin with.

The debug log exists for development reasons, and having the client automaticly delete the log upon exit would be self-defeating.  I suppose that a startup batch script that destroys the existing debug.log file upon restart wouldn't be too dangerous.  Or you could use the -noirc switch to disable the irc bootstrapping altogether.  You only need it upon the initial startup of a fresh install, or if you wipe out your database.  You don't really need it at all, it just makes finding the ip addresses of the first few connections easier.  After that, node discovery is done via the p2p network itself.  I always use -noirc.  You need to do it if you are using tor or I2P, otherwise the irc code will just leak out your ip address anyway.

You two are talking about two different things, Littleshop.  This wasn't the normal bump just after the difficulty change, nor was it normal statistical variance.  There were 11-12 blocks found per hour for several hours continuously.  Someone was benchmarking some serious hardware.

I still wouldn't get to worked up about it, anyway.  Whatever they had wasn't quite enough to capture the network, and since the network is always growing, their high end machine simply isn't up to snuff.

Do you restart your client often?  The debug.log is just a logfile that is recording events that your client considers notable, such as restarting.  You can delete that without a hickup, and the client will just start another upon the next restart.  blk0001.dat is the actual blockchain while blkindex.dat is the file that your client uses to quickly find a particular transaction within all those blocks.  I would still recommend that you backup your wallet.dat file before deleting anything, though.

So are X-box live points and WoW gold.

Not really, because at this point the client will still verify all the blocks upon first start, regardless of where the blockchain came from.  In the future, there are likely to be clients that come with a blockchain already in it and trust this included blockchain, but that would require trust in the client developers.

(7200 BTC per day * 7 days * 52 weeks) / (210000 * 50)
(2620800) / (10500000) = .2496 = 24.96%

I royally screwed that one up.  I apologize.  So dropping the block reward in half would drop the % APR to about 12.5%.  So was I off by a year?

(3600 BTC per day * 7 days * 52 weeks) / ((210000 * 50) + ( 52416 * 25))
(1310400) / (10500000 + 1310400)
(1310400) / (11810400) = 0.11095305832147937411095305832148 = 11.09%

Apparently not.

The other option involves pruning of the blockchain's spent transactions, which is already in the protocol, but not yet safely implimented into the client.  That is why transactions are stored in a merkle hash tree instead of just a flat file with all the transactions hashed once.  The merkle hash tree permits spent transactions to be deleted from the local blockchain without disrupting the verification of other transactions in the same block yet unspent.  The only part of the blockchain that must continue to exist is the headers, which weigh in at 80 bytes exactly for each block.  Roughly 4 megs per year. 

Not at all.  The link was talking about gold and silver coins with a qr code web address printed upon them.  Not a thing about rfid chips.

Normally, that would be the answer.  But this time some major miner turned on his cluster just after the difficulty change and ran it about 8 hours and shut it down.  If you look at the timestamps at blockexplorer.com it's pretty obvious that blocks were coming in at 12 per hour for about 8 hours then suddenly dropped back to six per hour.

EDIT:  It's also obvious that, whoever it was, couldn't manage to quite break 50% of the total network hashing power.  It might have been a test (by govco? Who else has that kind of power?) to see if they could still break bitcoin.  If so, bitcoin just barely survived.

Good luck with that!

Try not to be a dick, okay?

First, I didn't say that.  Second, libertarians are not anarchists.  We have a strict set of tasks that a good government should perform.  One of which is to protect the individual citizen from theft, fraud, etc.  Most of us accept teh premise that industries that profit from collective activities (i.e. governments) are also logicly subject to oversight.  Our problem is that it never seems to end there.


A truly free market needs no government oversight, but when a government participates in the market as either an overseer or a customer, it then distorts said free market so that it is no longer truly free.


There are, in fact, a set of natural laws that can be discovered by human reason.  I shouldn't even have to prove this, but I could.  They, however, can be boiled down into 19 English words, and are called "Maybury's Two Laws" or the "Two Laws of Civilization".  They were coined by Rich Maybury in his book, Whatever Happened to Justice?  They are as follows...

1)  Do all that you have agreed to do and...

2)  Do not encroach upon the person or property of another.

All natural, or 'common', laws flowed from this deep rooted concept of fairness.  The differences are borne of culture.  For example, what is property?  What is encroachment?  Are there any agreements (contracts) that an individual cannot make?  Is an individual bound to honor an agreement made under duress, or deception?  Generally speaking, civilizations that tended to honor those two laws (within the context of their own cultures) tended to prosper, while those that failed to honor those two laws tended to decline.  The accepted rules of free markets flow from these two laws naturally, and these can be collectively called capitalism.  As such, capitalism exists to some limited degree always and everywhere; from the black market traders of the strictest socialist nations on Earth to the unregulated digital halls of Silk Road.