It doesn't help you because you can't prove you got anything from random.org nor can you prove you didn't discard things you got until you got what you wanted. If you do choose to use it, make sure the casino commits to whatever it got from random.org -- otherwise you violate the "everything it will use to shuffle the deck but the user's seed" clause.

The community would have their choice of ways to respond and I can only guess at what would happen. Presumably, stakeholders would agree on the scheme that does the least damage. I would guess that this would be "rewinding" the block chain to the longest public chain just before the first absurdly large reorganization. Thus, people should be able to defend themselves if they stop trusting Bitcoin as soon as they see an absurdly large reorganization. (I'm not 100% sure about this. Don't go ahead and do it just on my say so.)

Actually, this might be a good rule -- if you ever see a block organization of six blocks or more, you should consider the Bitcoin system broken until you personally confirm that it is still safe. (Have we ever had a reorganization of more than six blocks for a reason other than the system being broken?) With reorganizations smaller than that, you are safe if you wait for six confirmations.

If you mine with a pool, the pool controls what block you build on. You can't trick a pool into causing a reorganization.

I don't want to sugar coat things, a 51% attack on Bitcoin would be bad. But I don't think it would be the end of Bitcoin. Too many people have too big an incentive to get the system fixed.

The biggest threat would be to miners because one obvious solution would be to change the mining algorithm and force the attacker to start over from scratch. But I don't think it's likely the community would adopt this solution -- for one thing, miners would oppose it.

For single player:

1) Casino commits. (To everything it will use to shuffle the deck but the user's seed.)
2) User reveals his seed.
3) Game is played.
4) Casino reveals.
5) User checks that casino revealed what it committed to, that deck was shuffled correctly, and that cards correspond to shuffled deck.

It wouldn't completely eradicate Bitcoin though. It would just shake people's confidence in it and require some very, very ugly solutions.

Mining pools could sign their blocks and could agree not to build onto a block that wasn't signed. Clients could prefer signed blocks to unsigned blocks in reorganizations. One or more distributed, high-speed checkpointing systems run by trusted individuals could be set up. Path dependency could be added to the "longest chain wins" algorithm. The mining algorithm could be changed, forcing the attacker to start over from scratch.

Your algorithm is not provably fair. The user has to reveal before the casino has committed.

The system is not provably fair unless you follow this kind of process:

1) Casino commits.
2) Users commit.
3) Users reveal, each doing so only after it has confirmed that it has received all commitments.
4) Casino confirms each user has revealed what it committed to.
5) Game is played.
6) Casino reveals.
7) Users check that casino revealed what it committed to, that deck was shuffled correctly, and that cards correspond to shuffled deck.

If there is only one player, then steps 2, 3, and 4 can be collapsed into the user revealing. The user does not need to commit.

This ensures no user reveals anything until the deck has been locked in. Otherwise, entities with special knowledge can change things after the user has given up his opportunity to influence the outcome.

You probably should have each user pick a random 128-bit seed. The deck can be shuffled with the XOR of all revealed seeds or with a hash of them (in a pre-arranged order, of course!). Commitment can occur by revealing a hash of the seed.

The main difference is that people who have trusted different exchanges can still make payments to each other.

A secondary difference is that the exchanges can't as easily target a single customer. If an exchange decides it won't let you specifically withdraw for some reason, you are pretty much stuck. If a Ripple gateway does the same thing, you can just trade your assets at that exchange for assets issued by a gateway that will let you withdraw. You can move funds into or out of a gateway without needing that gateway to perform each operation or subjecting it to arbitrary and unpredictable rules.

If you hold Bitstamp assets on Ripple and decide that for some reason you don't want to hold them anymore, you can sell them for XRP immediately without having to ask Bitstamp to perform the transfer.

While the value of dollars relative to Bitcoin will drop, the value of the dollars themselves won't change very much. For example, dollars will still buy about the same amount of gold, the same number of apples, the same number of Euros, and so on.

Bitcoin can only capture value it creates. Alternative currencies will have to create value in order to capture it.

The block reward needs to be a sufficient incentive to provide enough proof of work to keep the Bitcoin system secure until transaction fees have enough value to take over. If the block reward was too high, the price would keep dropping and everyone would be playing "hot potato" with their Bitcoins. If the block reward was too low, the network would be insecure and unreliable.

My guess is that Satoshi underestimated how successful Bitcoin would be and as a result there is much more mining than there needs to be.

Any suggestions? Is there some other way to say "this is obviously a Ponzi scheme"?

Code red! Someone is wrong on the Internet!

Warning the investors won't work if lessons aren't learned. We warned until we were blue in the face about Pirate, and not enough people listened. For reasons I cannot fathom, there appear to be people actively opposed to learning lessons.

How long did you wait between these last two steps? Did you confirm that the bitcoins were send to the public address? How many confirmations do they have?

PayPal has no control over chargebacks. They never allow or disallow them. They just happen and PayPal responds to them. Perhaps you're confusing a chargeback with a dispute?

https://www.paypal.com/us/webapps/mpp/security/chargeback-faq
"A chargeback, also known as a reversal, is when a buyer asks their credit card issuer to reverse a transaction after it has been completed. It is available only to users who make a payment funded by their credit or debit card."

What is the exact timeline of your actions? What did you do first? And how long did you wait?

Here's a tip for you -- you really don't want to look like you treat your customers badly in public. Even if a customer is a jerk, bend over backwards in public to make them satisfied. Otherwise, people wonder how many dissatisfied customers are keeping their mouths shut in the hopes that you'll make good and out of fear that you will punish them for complaining in public.

No. You can't. You have to look at how native speakers actually use the word. Really.

That is correct, widespread use is not quite equivalent to correctness. I'll happily point you towards sources that explain where the truth is between prescriptivism and descriptivism.

No, it doesn't. "Impossible" is not a measure of probability. It's not a mathematical concept. You can google "* is impossible" and take 50 random samples. The majority of them will *not* be using "impossible" this way.

Yes, that's exactly what I'm saying. Seriously, I just explained it. It's not hard to understand. If the person who claims there's a high chance of a profit is the very same person who claims it's low risk and expects you to trust them with your money with no legal recourse, that increases the probability that it's a scam. Yes. Really. (But the real point was that speculating in the price of Bitcoin is high risk and anyone who says otherwise should be ignored. If it was a sure thing, the price would already be higher.)

If you don't know how to use a dictionary properly, then it really doesn't mean much to me that you respect me. Dictionaries point you at the general concept of a word, actual use by native speakers is authoritative. Native speakers going to a dictionary to tell each other how they "should" use a word is flat out idiotic and flips the way language works on its head. (With the possible exception of words with which they're not familiar.) You are essentially arguing that the majority of uses of the word "impossible" by native speakers is wrong, which is insane.

Definitions don't work that way. You can't parse them like a lawyer to figure out what does or doesn't quality.

They were randomly selected. Impossible and improbable don't mean the same thing. Impossible conveys a much higher level of unlikelihood than "improbable" does. There is no common English term for actual metaphysical impossibility because it is only useful in metaphysics.

I know you're being deliberately idiotic but just in case anybody thinks you're being serious rather than playing a childish game of "gotcha", the difference is that nobody claimed that you should trust them to invest your money in Bitcoins because Bitcoins were certain to appreciate in this way and that such an investment was low in risk.

No, that's not what "impossible" means. That's a childish word game. In fact, that's a concept that is so rarely useful there is no need to give it is own word. I just picked four completely random uses of the word "impossible" in a Google search:

http://www.forbes.com/sites/johntharvey/2012/09/10/impossible-to-default/
"It Is Impossible For The US To Default"
This clearly means it is impractical under the current circumstances. But this use of the word "impossible" is not wrong. To respond to the writer of this headline that there are conceivable circumstances under which the US would default would be idiotic, and everyone knows it.

http://www.nationalreview.com/david-calling/355981/compromise-impossible-egypt-david-pryce-jones
"Compromise Is Impossible in Egypt"
Really? Compromise will never happen in Egypt under any conceivable circumstances? Really? Is this headline wrong?

http://www.poetryfoundation.org/poem/238710
Okay, this is a poem.

http://news.yahoo.com/blackberry-impossible-value-now-165548321.html
This uses the word "impossible" to refer to something that is merely difficult to do well. Wow, so many people don't understand how to correctly use the word "impossible".

Because that's how the English language works. That's what the word "impossible" means.

Can we stop the childish word games now? Please.

And I have no problem with that position. What I have a *huge* problem with is people who say things like:

"People who say "X is impossible" are amusing to me, regardless of X."

And

"It's not lacking common sense to say that something being a scam is not a complete certainty."

And

"Stuck in a loop: People who say "a legit business MUST X" are amusing to me, regardless of X.
It's like they've completely shut off the possibility that there could ever be people who know things about business that they don't know."

These are all things you said, and they are all foolish and harmful. Invoking notions of metaphysical certainty, in a conversation about anything but metaphysics, is an attempt to reject common sense and has the actual effect of causing people to make bad decisions. It is also, quite simply, wrong.

"Impossible" does *not* mean "beyond logical possibility". Buying a car that goes 300 miles per gallon of gas is not a logical impossibility, but it is also impossible. "Complete certainty" is a metaphysical concept. Its relevance to investing is nil. And "MUST" does not mean complete metaphysical certainty either.

That is all complete and harmful foolishness.

I totally disagree. In fact, to talk about what can be known with "complete certainty" is the very opposite of common sense. Common sense is about making decisions that will almost always be right given that we never have complete certainty. Common sense is not letting scammers sucker you in with arguments about how you can't know their obvious lies are nonsense with "complete certainty" and how you must always entertain the possibility that might have found some miracle. Common sense is knowing there are no miracles, not keeping your mind perpetually opened to the possibility that there might be so that you can be taken advantage of.

Common sense is knowing when *not* to keep an open mind. Common sense is knowing when you know something. Entertaining miniscule possibilities is the antithesis of common sense.

Are you opposed to learning a lesson on some sort of principle? People who say things that are phenomenally improbable and where they have an enormous incentive to lie, where they are anonymous and everyone in the past who has made similar claims has been lying, are almost certainly lying. This is an undeniable fact and the effort spent evading it and attacking the people explaining it would be comical if they weren't doing so much real harm to real people.

Nobody has ever found any legitimate, low risk investment that requires taking on more and more high interest debt, yet any number of scams are based on this. The probability that the person asking you for money will be the first is near zero, and absent some plausible explanation of how they could possibly be that person, only a fool would consider any other possibility than that it's a scam. This is simple, basic common sense.

Simply put, anyone who sees an absurdly high interest rate and thinks "what a wonderful opportunity" rather than "what an obvious scam" lacks common sense. And, honestly, anyone who suggests that the community ought not to learn this lesson, in my opinion, is most likely seeking to exploit that lack of common sense. There is no other reason I can think of to preserve it rather than combat it.