With a broken one, you're much better off with f(A|B) than f(xor(A,B)). If A and B have too many bits in common, the xor is a disaster.

Your better off concatenating and then hashing the concatenation to the needed size. XORing is not a good idea. To see why, consider which of these is safer (where | is concatenation).

1) XOR(SHA256(X), SHA256(X))

2) SHA256(X | X)

The former is zero no matter what X is. The latter is safe so long as X is safe.

Now, consider this. X and Y are fairly random but, due to a broken PRNG, only differ in a few bits. Which is safer:

1) XOR(X, Y)

2) SHA256(X | Y)

The former can be insecure even if both X and Y are secure alone because all the common bits drop out. 2 is at least as strong as the stronger of X alone or Y alone.

Nobody has reported having funds and then not having them where we couldn't find them having the funds in the first place. I hope he's just remembering incorrectly and the DYM was never sent or was sent to some other account. It should be impossible for funds to disappear, but even more impossible for history to show funds never having appeared in the first place.

He would have had to elect to pay with his DYM, and it would have had to perfectly consume exactly the 1 DYM he had, which seems unlikely unless he paid exactly 1 DYM to someone.

No. Only the price of Bitcoins at the time you buy the miner matters. Future changes in the price of Bitcoins more or less cancels out. The cost, in Bitcoins, of a particular piece of mining hardware is dependent on the price of Bitcoins. But after that, the Bitcoins mined can be compared to the cost of the miner in Bitcoins without regard for the future price of Bitcoins.

If I'm considering buying a piece of mining hardware that will cost me 50 Bitcoins today and can be expected to mine 70 Bitcoins over the next year, then it's probably a pretty good deal. The higher the price of Bitcoins, in fact, the better off I am with the miner because the lower, proportionately to the reward, the cost of electricity.

If you want to PM me your Ripple address, I'd be happy to investigate for you and either post the results publicly or privately. Obviously, that's not supposed to be possible.

It's actually slightly worse than that ecause if you buy 50 BTC, you can sell them any time you want. If you mine 50 BTC, you can't sell them until you mine them.

True, but the arguments rarely work out quite that way. You generally don't really know how many BTC you're going to get because future difficulty is hard to predict. But I absolutely agree that if you're trying to decide whether to mine, you should first compare buying mining hardware to buying BTC.

Sue the buyer.

Huh? Say a mining machine costs $5,000 and is expected to average about one Bitcoin per day over the next 3 months. If Bitcoins are $1 each, that's a lousy deal. If Bitcoins are $100 each, that's a pretty good deal. The cost of mining hardware is based on dollars because mining companies have to pay employees and suppliers that way.

That's not PayPal's fault. It's not their job to force someone to pay you if they don't want to. It's their job to make a payment from a willing sender. They also provide seller protection, but not for digital goods.

The problem is, he's focused on how to divide up the value without paying any attention to how to *create* the value that will be divided.

This won't help miners -- creating more coins doesn't create more value. All you've done is ensured that people who hold the currency get screwed by increasing difficulty as well.

That makes you a scammer, not PayPal. If you agree to pay for something and receive that something, you have to pay for it. If not, you're a scammer.

In your case, the buyer still owes you the money they agreed to pay you, since they didn't pay it to you. If they're honest, they should still pay you. If they're dishonest, then they scammed you. PayPal and eBay don't provide seller protection for digital goods, you have to sue the buyer.

Is there any link to the actual bug and the actual fix? I see descriptions of the affects of the bug and suggested workarounds, but not the actual bug itself nor the fix itself.

PayPal is quite clear that there's no seller protection from sales of digital goods or direct payments. In your case, the buyer still owes you the money and, assuming they still want to pay you, they should pay you. PayPal can't force an unwilling buyer to pay you money. PayPal makes reversible payments, period. The buyer pays you so long as the buyer wants to pay you.

Then you want to adjust the difficulty normally to keep block generate stable but adjust the block reward based on the difficulty, I think. The problem is that the rate of coin creation will increase exponentially through all time, making the coins most likely a lousy store a value.

If the hash rate goes up and the difficulty goes down, the rate at which blocks are discovered goes through the roof. How will servers agree on which chain is the right chain? Imagine you have 15 chains all extending at the same time at a rate of several blocks a second -- how do you make sense of that? The vast majority of mining effort will be completely wasted because it was built on a losing chain. This design makes no sense.

It depends on the type of encryption and the exact details of the bug (which, to my knowledge, still haven't been released). Generally, programs on "small" devices tend to use asymmetric encryption as clients and then they really don't have anything to compromise.

I would be surprised if Bitcoin wallets were literally the only programs affected, but I wouldn't expect there to be very many others.

No, I got you.

Right. PayPal decided to disintermediate itself, that is, it removed itself from the payment between you and the buyer. I'm assuming PayPal returned the funds to the buyer, and the buyer should have paid them to you. PayPal makes it very clear that their deposits are reversible and will be reversed if payments violate their ToS or if the buyer no longer wishes to make the payment.

Not knowing what evidence you presented in court or what arguments PayPal made, I can't tell whether the judge's ruling is correct or not. But just from what you said, PayPal didn't do anything wrong.

Again, I very much dislike PayPal. They massively screwed me over. I'd be the first to agree if they did anything wrong. But PayPal makes reversible payments, period. And PayPal reserves the right to remove themselves from a transaction they don't wish to be part of.

No. The issue has nothing to do with exposing encrypted data but with signatures exposing private keys.