Think harder. Suppose someone obtains bitcoins through some illegal activity (which the police find out about), they sell them to you, then the police will know that you received bitcoins from an illegal activity, and they will get a subpoena for the seller's name and bank account details. As a perfectly legal company, you will hand over this information, and the seller gets arrested. But that's not your problem, the problem is with criminals being complete morons and thinking that using bitcoins magically makes them anonymous. Hint to would-be criminals: If you obtained bitcoins illegally (or have any other reason to remain anonymous) and need to sell them in a way that can be linked to your name and bank account, use a damn mixing service ffs.

a. 70%
b. less than 49%; how much less depends on how many houses are in the suburb, eg if there are 100 houses, the probability is 48.788%

What do I win?

Your colleague clearly has no clue. Only certain types of public-key cryptography (including ECDSA, which is which is what Bitcoin uses) are especially vulnerable to quantum computers. Symmetric cryptography and hashing algorithms are slightly weakened, but not to the point of being "broken". Note that there are public-key algorithms which are not broken by quantum computers, and Bitcoin can switch to one of them if the need arises (the reason Bitcoin isn't using them now is because these quantum computer resistant algorithms are relatively new and untested and may have as-yet unknown flaws).

If Bitcoin becomes successful, they stand to gain billions by working with it rather than against it (sure, it's not worth billions now, but it will be if it ever reaches the stage where it becomes a serious "threat"). And if it doesn't become successful, why go to the trouble?

The other thing is that as bitcoins increase in value, mining becomes more profitable, which means more people will mine, which makes it harder and more expensive to pull of a 51% attack. When Bitcoin is worth enough to pose even a slight threat to the banks and governments, it will have much, much, more security.

You're confusing nominal value with real value. A 51% attack can't be kept secret, it will be discovered pretty much instantly, and then who's going to buy your bitcoins or accept them as payment? Nobody, that's who. If there's ever a 51% attack, the attacker's coins (along with everyone else's) will be worthless, and if the attack continues for any length of time, they'll never recover their value as all faith in the security of the network vanishes. Alternatively, you could decide to not orphan everyone else's blocks, and then nobody will be the wiser, there'll be no drop in value, and you get to keep 51% of everything. I'd much rather have 51% of something valuable than 100% of something worthless, but maybe that's just me.

What are you suggesting? That a political organisation might turn down a massive bribe? Maybe you're forgetting just how massive it is. We're talking about 51% of all transaction fees, plus 51% of all newly-created money, of a worldwide currency. That's a central banker's dream (well, they dream of complete control, but I think they're all aware that's never going to happen with a world currency). You really think anyone would rather try to destroy us (with no guarantee of success, I might add) than take a 51% cut? I don't.

If you have 51% of the network hashing power, there are two things you can do with it:

• Secretly (but entirely legitimately) mine more bitcoins than the rest of the network combined, making you insanely wealthy; OR
• Do a 51% attack, which cannot be done without the rest of the network knowing about, causing a mass panic and a loss of faith in the system, greatly reducing the value of any coins you mine.

These options are mutually exclusive. You can either get rich or attack the network, but not both. There is a very strong economic incentive to not perform a 51% attack. A built-in bribe for potential attackers, if you will. Of course, a politically-motivated attacker might care more about disrupting the network than their own wealth, but really, what are the chances of that ever happening?

Correct. Also (in the standard client at least), when you try (and fail) to send, the address in question will be highlighted in red to indicate that is invalid.

No, since Bitcoin addresses include a checksum for exactly this reason. The chance of a mistyped address being accepted as valid is 4,294,967,296 to 1.

That's true. SatoshiDICE gives you better odds of getting your money back.

That's a horrible thing to say. You really need to be more considerate to blind people.

References to Tormail and Bitcoin removed.

You seem to be a little confused about what Bitcoin is. Bitcoin is two things: it is a currency and it is a payment network for that currency. Nothing more. There are various exchanges which allow you to trade bitcoins for other currencies in the same way as regular forex markets (though I don't think many (if any) currently offer options, though it is likely they will once the market is more mature), but Bitcoin itself is not a forex market.

The Bitcoin market is currently not very liquid at all, with a market cap of only $140M, and only a tiny fraction of the bitcoins in circulation are actually available for sale on the various exchanges. You will have much trouble buying or selling bitcoins in large amounts (depending on your definition of "large").

The standard client requires 1 confirmation, except for change, which can be spent with 0 confirmations (since change is sent from yourself, to yourself, and thus guaranteed to be legitimate). There is a (moderately expensive) attack against 1-confirmation transactions, though you needn't worry about it unless you're dealing with a relatively large amount of money (and then you just wait for 2 or 3 confirmations). Waiting for 6 confirmations as suggested by others is almost certainly overkill, and there's nothing special about that particular number that makes it "safe" (Why 6? Why is 5 not enough? Why not be extra safe and wait for 7?).

Eligius (and p2pool) don't actually "send" you coins, instead you get your coins direct from the block reward, which takes 120 confirmations (about 20 hours) to "mature", in case of a blockchain split (which would render the block reward invalid along with all transaction spending it).

I used to hold a high opinion of blockchain.info. Now I don't. What's with this blatant censorship? And why only this particular transaction, and not all the similar "offensive" ones? And more importantly, why weren't we notified of this? I demand an explanation. Dammit, we're never going to get to the bottom of this if you just silently unexist these notes wherever they appear. Besides, you're a blockchain explorer, and this information is supposedly in the blockchain. Suppose I went to the police about this (pick up your jaws, I'm speaking hypothetically here), and pointed to that page as evidence, but - oh, no, it's gone, with no record that it ever existed in the first place. Now I look like the crazy person. Seriously, what the fuck?

Makes no difference, since the market will give food stamps value (even if it's illegal to trade food stamps for cash, people will do it anyway).

Nor would they be if you weren't printing and giving away money, so how is that even relevant?

Instead, everyone has to pay, although the rich still pay more, for reasons I will explain below.

The free market will adapt by making the money worthless. Supply and demand. The demand for money is fixed (since people can only produce so much stuff to sell), so if you have an ever-increasing supply, the value will inevitably plummet.

No it won't. There is no end. No matter how much money the working people make, the non-working people still keep getting their free money.

True. And that is a bad thing. Why would anyone think that's a good thing?

Guess again.

It is bound to specific thing (your money), and therefore it does matter how rich you are. If your money is being devalued by (say) 10% every year, and you have (say) $100,000, then that's exactly the same as paying $10,000 tax per year. If you have $1,000,000, you're paying the equivalent of $100,000 tax per year.

It is not being added, for there is nothing to add. As I said, the demand for money is fixed, so every dollar that you print is a dollar deducted from the collective purchasing power of everyone who owns dollars. By distributed those dollars to everyone whether they're working or not, you are stealing from everyone who has money (and presumably worked for it), and giving to everyone who doesn't (ie, those who aren't working).

The gap between the working and non-working people will decrease, not increase, and that's bad. It punishes people who work and rewards people who don't.

Better than what we have now isn't really saying much.

It's not exactly the same. I neglected to mention that inflation, unlike taxation, is an invisible sack of shit. But it stills stinks, and everyone knows it stinks, though the uneducated can't tell where the stink is coming from.

Same shit, different sack. If you don't understand why these are exactly the same shit, you've got more reading (or thinking) to do.

Article is 404 in Australia. Full text:

Isn't it? I thought blockchain.info's public notes were encoded somehow in a zero-value output, making them permanently part of the blockchain. Enjoy your permanent label. (I'm in that transaction, too, BTW, and I'm just as confused as you are.)

It looks like Raided for Tor has been getting several such messages over the past couple of days, from such addresses as 1KiDSxM3tZ3VAkRFYu4CnTv51xdEbMmEJP, 1CHiLDqtigm7sMkZpGF9KahVJgkQiWGUAo, 1CPxxxSHcKupLcqUf76FxBTe2DuXtVeqwn, 1pedo9hWm94NriUuDPnZqeWddPGna81Dv. Looks like someone's trying to make a statement, although why it's addressed to us I'm not sure.

Apart from the fact that very few people actually use brainwallets (I'm being very liberal with my interpretation - one's brain and forehead are really two completely different body parts), you can transact with bitcoins right now without ever seeing a private key. And you always will be able to. In fact, it is likely that in the future, most people will never see a private key, instead trusting their bank to handle all the "technical" stuff for them (which, considering most of the general public has yet to figure out how to download porn without infecting their computers with half a dozen viruses simultaneously, is probably a good idea).