Bitcoin address X contains 1.06 bitcoin.

Let's say a miner sees two unconfirmed transactions broadcasted - the first one says to send 1 bitcoin from address X to address Y. The second transaction says to send 1 bitcoin from address X to address Z. Both transactions cannot be completed. This is a double spend.

My understanding is that Bitcoin miners can write their own miner software to choose which transaction to process in any way they wish. They could include in the next block whichever transaction has the higher fee, they could go with whichever transaction they received first, they could go with whichever one has more of the letter 'Q' in the destination address because they like the letter Q.

But in practice, how would this normally be handled by most miners' software?

I want a Gmail replacement with a few gigs of storage, without ads or without anything that reads my emails, run in a country that is outside the reach of United States National Security Letters (Iceland? Switzerland maybe? Ecuador?) And I'd really prefer a reputable entity running this.

I'm willing to pay for this in Bitcoin. Does such a thing exist?

So I'm trying out Coinbase for the first time, and I'm waiting on my account confirmation, but in the meanwhile it says "Buy Amount ----- at $98.87 each"   - but mtgox is showing their last price at $112.50  There can't possibly be really that much difference (~14%) between the two, can there? What am I missing?

Here's an idea I had while mowing the lawn this afternoon.

There are many times when I see a new Bitcoin business and I have no idea whether it's legit. So I have to ask around to find out, hope some people respond, and then check to see if the responders are long-standing members of the community or sockpuppets, and so on.

There should be an organization similar in concept to the Better Business Bureau (yes, I know the BBB is a flawed organization but we don't have to adopt the flawed aspects) and the Good Housekeeping Seal of Approval. This organization should issue approvals to certain Bitcoin businesses which have good reputation for honesty and upholding contracts. Maybe have a secure image they can feature on their website touting their status, or just a listing with a letter rating. Decisions would be made by consensus of a committee of upstanding members of the community.

Having such a trusted organization would be very helpful to people who can't spend lots of time on these forums every day, keeping up with Bitcoin news.

Does such an organization already exist? If not, who would be interested in getting this moving?

It's unlikely, but possible, that someone could break ECDSA or SHA256, which would be bad for the Bitcoin community.

What would be the drawbacks of using two methods of encryption, one on top of the other, so that if either one is broken, Bitcoin remains unaffected?

I presume it would be far less likely for two distinct forms of encryption to be defeated at exactly the same time, than to have one broken.

Are there strong, well-tested encryption schemes that are based on mathematics sufficiently distinct from ECDSA?

Side question: Do there exist viable forms of cryptography which are thought not to be defeatable by a quantum computer? I've heard of "Unbalanced Oil and Vinegar" which is supposed to be quantum-computer-resistant but not thoroughly tested.

Just because you started a thread does not mean you should have control over when other people must stop talking in it. That's not how discussions work face to face and it's not how it ought to work here. JMHO.

Perhaps an exception should be made when a person posts a thread in an appropriate specific subforum about their own Bitcoin business, but certianly not for general discussion about things like 'bitcoin users should never call the police'.

Spendbitcoins used to but it's not working now. Is there anywhere else that will do this? Or someone with a good otc rating that would like to do this?

Thanks!

[Do we want to keep the maximum block size large enough that all transactions can be included in every block, or do we want to keep it small to increase tx fees and incentivize mining?]

I'm sorry if this has been beaten to death already. I couldn't find the right search word to find if this was sufficiently discussed before.

As all we know, the block reward halves every 4 years or so. At some point it is going to get so small that miners will lose the incentive to mine if they don't get enough in transaction fees. So the big question is, what are transaction fees going to be worth?

At first I thought this wouldn't be a problem, because there's a limited block size, which means that if Bitcoin grows to be popular enough to fill entire blocks to the max size, people wishing to send Bitcoin transactions will have to outbid each other to have their transactions included.

But I recently read that it's expected that the maximum block size will increase. Who decides this? On what will they base their decision?

What happens if a miner tries to generate a block that is larger than the maximum block size? Do other miners reject the block and keep on mining?

Do we want to keep the maximum block size large enough that all transactions can be included in every block, or do we want to keep it small to increase tx fees and incentivize mining?

Right now I think there's about zero chance of anyone running a 51% attack on Bitcoin. Maybe it's even too powerful to be justified. But my understanding of the game theory of this is that as long as we haven't hit the maximum block size, rational profit-maximizing miners will include all transactions that have a nonzero transaction fee. That's the best policy for them to maximize mining profit. Your typical rational cost-avoiding Bitcoin spender knows this, and will then attach a 1 Satoshi transaction fee to each transaction. Under this situation I don't see transaction fees as being sufficient incentive for people to mine - unless there is scarcity of block size, in which case bidding between spenders for inclusion in blocks should drive prices up to the point where it sufficiently incentivizes mining.

(The other option to keep mining incentivized is to stop halving the block reward at some point. Keep it at that block rate forever, say, 12.5 BTC. The inflation rate will approach zero percent, and we'll still have the hardest money system in the world even if we're not capped at 21 million BTC)

Joy of joys!

http://bitcoin.sipa.be/

The 3-day window estimate is above 15 TH/s

Who is in charge there? Is there anything that can be done to fight back against the spammers?

If someone sets up an auction for this, I will be very interested. Also looking for a crisp new Canadian $100.

. . . and abandon its support for Mt.Gox. Will things keep on going smoothly without them? Maybe it will not make a huge difference, we have BitInstant, but it is something to be aware of.

I am virtually certain they will get bought, it happens to so many similar companies.

How do they not have the same problems with chargeback fraud that Bitcoin sellers have?

http://bitmit.net/en/trade/i/2324-1945-walking-liberty-half-dollar-us-90-silver/

Preferably from someone with a reputation to uphold.

On my old phone, I was using the Android app "Bitcoin" from Bitcoin Labs. I had .02 BTC on it. When I got my new phone, I installed Bitcoin Wallet (by Andreas Schildbach) and tried to send my BTC .02 from my old phone to my new phone. Well, the .02 disappeared from my old phone and never showed up on the new one.

Looking in the Android market, there are a few other people who wrote complaints about Bitcoin Labs saying that either their funds did not appear when sent to Bitcoin Labs, or that their funds on Bitcoin Labs did not appear when sent out.

I have waited several weeks and the funds never showed up on my new phone. I sent funds from my computer to my new phone and that worked fine.

So, my question is, is the Bitcoin Labs app just buggy, or is this a scam and someone is taking all the funds? Is there some way to check?

https://bitcointalk.org/index.php?topic=1958.msg740628#msg740628

I see these silver and copper Bitcoins (not the ones that have embedded Bitcoin codes) and I have to wonder if they are a good thing for Bitcoin - even an above-average person is going to get the wrong impression from these and think that Bitcoin is something physical, made of precious metal, when that couldn't be further from the truth. Why confuse things?

I'm not opposed to AOCS in any way, I think that's a good thing on its own, but it shouldn't be combined with Bitcoin when it is completely unrelated.

This seems to be a prime use for Bitcoin: A place for online auctions but without the Ebay restrictions and fees. A few have been made, like Biddingpond, bitbid, and a few others I can't remember, but none of them seem to have more than a small handful of auctions at any time.

What is missing from these websites that would make them take off?

I apologize if this belongs somewhere else -

Does anyone know why certain stocks will have moments where the trading price drops significantly, just for a moment, and then goes right back to where it was?

For example, yesterday, Tuesday the 20th, on this stock for SPY: (30 minute chart)



Looking at a 1-minute chart tells me that that entire drop occurred in less than one minute.

Someone told me that this is the "market maker" "pulling out the stops," implying that there is a person who arranges buys and sells who wants to punish people who have a lot of stop-sells on a certain stock, and who momentarily prevents higher-price buyers from being able to buy.

1. Is there a person consciously and actively doing this?
2. Why would he do this? Is there something bad about a lot of people having stop-buy orders in place?
3. Does/could this situation ever occur the Bitcoin markets? I imagine not since I don't think mtgox allows stop orders.

Let's say a person drops a few million bucks and now has 51% of the network hashing power, and he wants to run the 51% attack we hear so much about. What does he do?

My understanding is that he makes a payment to a person for goods, receive the goods, and then quickly make a second payment to an address he owns. If he happens to mine the next block (which he will with 51% probability), he includes the payment to his own address in the block but not the payment to the person who he received goods from. Then what? Will all further blocks reflect that the first transaction to the defrauded person never happened and the second transaction did happen?

The problem I have with my understanding of this is that there is only marginal benefit to having 51% of the network - having 51% of the network only allows you to double spend 51% of the time. But if you had 40% of the network, you would be able to double spend 40% of the time, which is still a pretty serious problem. There's nothing really special about getting 51%, right?

Is my understanding of this wrong? Thanks.