So the mystery miner seems quiet at the moment, nonetheless...

One of the elegant bits of bitcoin is that you can't start hashing a new block until you know the inputs, that is the new transactions you're going to have to hash, amongst other things.

If you decide to mine empty blocks, you take away one of the 'freshness' inputs that mean you can't work on the hash 'before time'. You are left with the hash of the previous block, and the time of your new block (am I right this is an input to your hash too ?) as things you're going to have to guess to get going early.

Normally the previous hash would be a large number, up to 256 bits, infeasible to exhaustively search while also searching for low hashes. However the bitcoin protocol also means that you know something about the previous hash, it meets the difficulty requirement, so your search space is reduced.

With a combination of choosing a time sufficiently far in the future and hashing with low input hashes only (changing the hash rather than the seed for instance), is there an advantage to be gained over other miners by trying to compute before the previous block is published ? Is this advantage increased if you wait until you have two valid hashes in a row before deciding to publish one ( if that's it, this should be easy to spot in the delay between mystery miner after someone else vs after himself) ? If there is an advantage does it increase as difficulty gets harder, making empty blocks trivial to find when difficulty is near the end ? You also have to gamble with the times, did the mystery miner blocks have odd time stamps ?

I'm sure you can set me straight, I have a nagging feeling that one exhaustive search is as hard as another in this case, at least until a long time in the future, so I should just accept that there's a lot of new hashing power, but if there's anything in this I would support moves to restrict empty blocks - this would comprehensively prevent such an attack

Hi whitelist request please

I have a startup that accepts bitcoin, know something about the internals of a smartcard, have been buying and selling since $0.20, have wanted to comment on various topics, and want to test an idea on a current thread...

Camem

If it matches one that's there I've had it take a couple of minutes but not more. If no-one's already bid something that matches then you're waiting for another user to buy your deal. You'll be first in the queue but watch the mtgox price movements, if they go against you you could be waiting a while. If you want to deal now, cancel your order and put up another one that's the other side of some orders you can already see.

No your blocks haven't fully downloaded - your transaction is alive and well but first appeared in block 137456

http://blockexplorer.com/address/1NbGWAqYZ5rR23ZoPGN2ye1VUbTAASiUMC

So you need to wait for the rest of the blocks to download. The windows client does sometimes seem to get stuck downloading blocks - might be worth closing bitcoin (exit, not just minimise) and starting again to kick it off again

Thought this was worth registering for...

"HMRC, the UK government's tax-colllecting body, says people do not incur a tax liability when trading in bitcoins as long as they do not turn their profits into regular cash. Once conventional money is involved, however, the income could become taxable, HMRC told New Scientist"  

This is an excerpt from the weekly print edition of New Scientist which came out in the UK last week (date on edition 4th June) - it's largely positive, compares Bitcoin to Paypal and Skype, and has an interview with Andresen

Preview here but registration for the full article
http://www.newscientist.com/article/mg21028155.600-future-of-money-virtual-cash-gets-real.html