Bitfloor, the fourth largest exchange dealing in US dollars, has just announced[1] that it has been hacked, and the service has taken a loss of 24,000 BTC, worth about $250,000 at the time of the theft. As Roman Shtylman, the founder of Bitfloor, describes it, “last night, a few of our servers were compromised. As a result, the attacker gained accesses to an unencrypted backup of the wallet keys (the actual keys live in an encrypted area). Using these keys they were able to transfer the coins. This attack took the vast majority of the coins BitFloor was holding on hand.” As a result, BitFloor has paused all exchange operations and, depending on the effect that this will have on BitFloor’s finances, BitFloor may take one of two options. They may either take the loss and continue running in an attempt to eventually earn the money back or, in the worst case, shut down entirely and begin an account partial refund process out of the available funds.

The unencrypted backup that allowed the thief to carry out the attack was made when Shtylman made a manual upgrade earlier and put the data into an unencrypted partition on his disk; Shtylman has so far declined to comment further on the details of the attack, saying that “my current focus is on the future and not the past.” As Bitcoin security experts point out, Bitfloor made not one but two errors that were both necessary to lead to such a severe loss; the first, leaving data stored unencrypted, was an honest and perhaps unavoidable mistake, but it would not have had nearly as much of an effect if there had not also been the second error of leaving so much money in an online-accessible “hot wallet”. Since the Bitcoinica Linode theft, in which an unknown attacker made off with $222,000 worth of bitcoins from Bitcoinica’s hot wallet in March, it has been generally understood that any Bitcoin-holding service should keep the vast majority of its funds in “cold storage”, a term referring to a setup where the private keys never touch any computer that is accessible from the internet.

All

monetary systems tend towards corruption.

The demonstration you're referring to relates to the impossibility of brute-forcing large keyspaces. Shor's algorithm is useful specifically because it is not a brute-force solution. (Grover's algorithm isn't a brute-force solution either, but only reduces the effective search space by a square root, so can be countered by simply doubling the key size).

If quantum computing ever becomes an issue, I suspect the loss of bitcoin's keyspace will be among the least of our worries. It would be a very different world.

What I'd like to know is why some letters have higher probability than others? Is that because some letters are more likely on the elliptic curve vs not? If you plug sequences into vanitygen it will give different difficulties depending on letter, eg.

11... > 1A...
1Q... > 1D...
1R... > 1Q... and so on.

I made a table of the first three chars after 1 to help me in a project with fast lookup of difficulty calculation. There are broad classes of probabilities depending on what letters are involved. I guess there is some non 1-1 mapping from 2^160 possible addresses and base 58 representations.

Not to hijack the thread, cuz i'm sure other people will read and be curious abut his too: But can some one quickly explain why its also very unlikely to accidentally type a valid Bitcoin address.  They are 33 (32 unique) case-sensitive alpha-numeric digits (Base 58).  Only a subset of all possible combinations are valid addresses.  What is the method and explanation for this?

Can some one also explain how if a public address is a sha hash of a public key, how can an address be signed by the owner of the privkey, if the public address can't be reversed into the full public key  (the key pairs are 256 bit ECDSA right?  Should be loner than 32 characters).

L'intro du bitcoin est juste légendaire : 

I don't know what you had for breakfast, but I hope you realize this doesn't make sense AT ALL.

Again, the future price is set by the wealthy influential investor not by "rational" investors.

If investors invest without complete, exhaustive, public information about what is it they are buying, they are NOT rational, by definition.

By the way, the pump and dump strategy is a known scheme that has worked many times (ever heard of Enron) even though it's considered a fraud in most jurisdiction.

The problem is that anyone who understands this strategy can get the same profit he does without any of the expense.

Say the long-term, fair market value of bitcoins is around $10, and that's roughly where they would be if nobody manipulated them.

That assumes he's the only one buying, though. He may be able to do this once, but when he tries it again (say next weekend) he'd find it harder to get away with.

So you're saying... he'll sell $1 of Bitcoin, sending the price down, then buy $1 of Bitcoin, sending the price up... and then he'll profit from that over and over?

Interesting business idea. Let me know how it goes.

There is zero danger of having one entity with 500k coins. The WORST outcome is if that person dumped all coins instantly. It would crash the price. Then what would happen? People like myself would buy up the cheap coins, the price would find some new stabilization level, and the "grave danger" would be gone. Someone with that many coins can crash the price, but only once. Problems solved.

It's a non issue.

ok merci, je ferais des copies la prochaine fois.

en même temps c'est logique, c'est comme des billets de banque, si je brule un billet de 10€, personne ne le récupére, il disparait définitivement

Les détracteurs diront que bitcoin réinvente ainsi ce qui existe déjà et ils diront que ça prouve que bitcoin n'apporte rien de neuf au système.

That was my initial thought too, because something that was relatively innocuous is now on CNN, etc. However, in reality, the affiliate card programs generate transaction/fee volume for MC; they don't care if it's a Planned Parenthood card or an ACLU card or an NRA card. I doubt that this has put bitcoin on any 'special radar' (it's no different than selling bitcoin on your own and putting the value on your Wal*Mart debit card.)

I believe that the BitInstant card will receive approval. The thought that Mastercard is intimidated by bitcoin is funny, because they could co-opt BTC momentum at any time by just adding it to the list of 158 other currencies that they authorize and clear in. Bitcoin is another currency to Mastercard and the chargeback and consumer protections provided by that network are value-adds for certain transactions.

yet another thread where the OP makes a FUD statement and then disappears unwilling to defend his position b/c he knows he can't.

Pour envoyer 100 euros à un ami à l'étranger par exemple, il est possible de convertir ce montant sur l'une des places de marché de gré à gré où s'échangent les bitcoins (il en existe une petite vingtaine dans le monde) puis de l'envoyer par Internet. Une fois le transfert opéré, le destinataire peut à son tour convertir ses bitcoins dans la devise de son choix. «  Il n'est nul besoin de déployer un réseau intercontinental, une connexion Internet suffit : les coûts d'infrastructure sont donc quasi inexistants. Contrairement aux réseaux privatifs existant, comme Visa ou Mastercard, le système n'a pas besoin de commissions importantes pour être rentable », conclut Gonzague Grandval, président-directeur général de Paymium. Cette société de solutions de paiement a d'ailleurs créé une application mobile baptisée « Paytunia » permettant d'envoyer et de recevoir des bitcoins et de les convertir en monnaie traditionnelle.