Have you ever thought of a coin with a changeable, maybe even regularly newly generated hashing algorithm? E.g. using the ID of the previous block as seed for generating a random hashing algorithm for the next block?

This would have the great benefit that it is way harder to build specialized hardware for the algorithm, thus allowing more people with normal hardware like CPUs and phones to take part in the mining process.

Current BTC-style cryptocurrencies (decentralized by use of network's majority of hashing power decision) already use something like this: changing the requirements to the hash is already similar to changing the hashing algorithm, or more generally speaking, the proof-of-work-algorithm (reversing a hashfunction is just one example of possible proof-or-work algorithms). But what about changing the order of operation, the operations themselves, or generating all operations of the hashing algorithm randomly? This would be impossible to meld into ASICs, leaving this technology completely out of the race.

Thanks for your replies. The conclusion is that it's just at the border where it theoretically makes sense to mine, but then it's really not worth the trouble.

It's perplexing that a new computer which is virtually for free can't mine anymore. I wonder if it is possible to create a coin which will always be mineable on standard hardware such as CPUs.

Hi Guys,

I just bought a pc with these specs:
CPU: i7-4700MQ max 3.4GHz, quadcore
RAM: 16GB
GFX: NVIDIA GeForce GTX 780M, 4 GB Memory

I understand it doesn't make sense to use non-ASIC technology for BTC mining.
But does it make sense to use it for mining any altcoins?

I bought this computer for my personal use anyways, so if I can mine a few coins, even if it's just for fun, then I would be happy to do it.

MtGox disabled trading today, 25th Feb, at 2am GMT.

I initially saw that there were no price changes and then realized that there are also no changes in the order books.

I then tried to do a test trade and the result was the message "Trading has been disabled": https://i.imgur.com/o7KKjrM.png
I haven't taken this screenshot, but it looks exactly like what I see on MtGox when I try to submit an order.

From a former quote, here is your lawfirm:

Man, keep quiet. Don't tell everybody. Keep the price as low for us as possible.

I think many of you are curious about the outcome at MtGox. I, for my part, am very curious. Let's see what the majority guesses.

I like the poll "What do you think is going on between CoinDesk and Mt.GOX?" at https://bitcointalk.org/index.php?topic=471627

Because the poll seems to be partly for entertainment, I voted Mt.GOX broke Coindesk's heart and now CoinDesk is like an angry ex.. However, I do think this comes close to the truth.

cf. "Does coindesk.com write for payment?" https://bitcointalk.org/index.php?topic=473497

Interesting to see that the OP doesn't even consider "CoinDesk is trying their best to give unbiased, original, well researched information to its valued users.", which indeed sounds like a parody.

I fully agree.

Interesting. What kind of information source do you have for this? Do you have an explanation why they on one side seem to have good to outstanding knowledge of the matter, but on the other side they write articles saying more or less the opposite of what are known facts?
After reading the other posts in this thread, your claim is not convincing without supporting references or naming the source.

Google guidelines are not a law. They don't need to follow this. There would be no consequences for them as long as they pretend they do not receive payment. Hence this is not an argument.

Just a thought crossing my mind. I read on coindesk.com an extremely positive article about butterfly labs. And an extemely pessimistic one about MtGox. That latter one might turn out to be true, but it's merely based on speculation, which is a weird thing from a news site.

What do you guys think? Do they write for money and thus they are strongly biased and are good for nothing else than entertainment, or do they write the results of unbiased journalists' original research?

You're right in this regard. Writing a question that people can read and speak out automatically makes them think that they understood it. At least something I learned through this thread.

It seems that most misundestood my post. Most only thought about the double spending problem in the domain of bitcoin. But my question is more general. The double-spending problem is not limited to bitcoin, but most people here only think about bitcoin when talking about double spending problem.

That is not correct, as the double spending problem is a more general one. Bitcoin has one possible solution to the double-spending problem, which is trusting the collective party which controls the majority of the network's hashing power.

As stated, there are many possible solutions to the double spending problem. Other solutions than that of bitcoin usually involve a centralized trusted party, e.g. linden dollars or the taken down liberty reserve. But all of the known solutions involve trust in some way. My question now was not about bitcoin. It was about the more general double spending problem and if there exists a mathematical proof that the double spending problem can only be solved with trust in one or the other way, or if this proof does not exist, if it might be possible to find a solution which does not involve trust.

Yes, I'm very aware of all the trivial prose intuitive explanations why trust is required. But prose explanations can mislead, while mathematical proof is guaranteed to be correct (provided there is no mistake in proof and premises).

I'm aware of them so you don't need to repeat them here, please! And I know bitcoin's solution to it extremely well, so please also don't explain bitcoin's individual solution here any more. I know it.

Finally, if you are not a maths pro, don't comment here.

Is there mathematical proof that the double-spending problem can be solved only by a trusted party, be it network majority, central trusted party, something in between like a trustweb, or even directly trusting the sender of the money? (Yes, if you trust the sender, there is no need for a third party.)

cf. http://en.wikipedia.org/wiki/Double-spending

From intuition, it is quite clear that without trust, the double-spending problem can't be solved. But intuition can often mislead. For that reason: Is there mathematical proof that trust is an implicit requirement for solving the double-spending problem?

I'm using MtGox's PubNub API to fetch ticker data. I've subscribed to the BTC/EUR ticker with id 0bb6da8b-f6c6-4ecf-8f0d-a544ad948c15 . In more than half the cases when I receive a new ticker message, the data is just the same as that of the previous message, except for the timestamp of course. I expected ticker messages only when there is new data available, so I do not understand why the ticker messages get repeated. Examples:


diff_to_previous  instant_________      last_all        last_local      last_orig       buy_____        sell____        vwap____        vol_____________    item  avg_____      high____        low_____
n/a               2013-12-12 16:31:46   EUR 628.31408   EUR 620.22000   USD 865.00000   EUR 620.22000   EUR 629.00000   EUR 647.91649   BTC 1365.61335998   BTC   EUR 649.27938 EUR 680.00000   EUR 615.00000
none              2013-12-12 16:31:50   EUR 628.31408   EUR 620.22000   USD 865.00000   EUR 620.22000   EUR 629.00000   EUR 647.91649   BTC 1365.61335998   BTC   EUR 649.27938 EUR 680.00000   EUR 615.00000
none              2013-12-12 16:31:53   EUR 628.31408   EUR 620.22000   USD 865.00000   EUR 620.22000   EUR 629.00000   EUR 647.91649   BTC 1365.61335998   BTC   EUR 649.27938 EUR 680.00000   EUR 615.00000
last_all          2013-12-12 16:32:05   EUR 617.41846   EUR 620.22000   USD 850.00000   EUR 620.23000   EUR 629.00000   EUR 647.91649   BTC 1365.61335998   BTC   EUR 649.27938 EUR 680.00000   EUR 615.00000


What kind of events trigger a ticker message to be broadcast?

This question is also on http://bitcoin.stackexchange.com/questions/18611/why-are-ticker-messages-in-the-mtgox-pubnub-api-repeated .

welcome in the forum!

Just thought about the same. I think it's soon time to lower the fees.

For acquiring some play money, you can also try to find a working bitcoin faucet, which gives away a very small amount of btc for free. If you search and you can't find one, I don't mind giving you 2 dollars in btc.

You use signing to prove to someone else that you are the owner of a bitcoin address.

The most common purpose to do so is when you pay something to someone else: You use the address from which you sent money to sign a message containing your purpose of the payment. This way, the recipient knows who paid him and nobody else can claim that he made the payment.

For example, a signed message could look like this for such a purpose:
message: "i am forum member xyz. as agreed, i sent you btc0.1 for exchange to USD. please send the USD 75 to bank account ..."
signing address: ...
signature: ...

Signing the purpose of a payment with the sender address is important, because everybody can see your transaction to the recipient (transactions are public) and if someone else knows the recipient, this person could tell the recipient a made-up story why he paid this to him and claim the return (goods, other currency, ...) for the transaction.

Probably the most comprehensive list of ways how to get bitcoins (exchanges, foundries, etc.) is here:

https://en.bitcoin.it/wiki/FAQ#How_can_I_get_bitcoins.3F

Any usually you will just buy them at an exchange:

https://en.bitcoin.it/wiki/Buying_bitcoins

I used MtGox so far and had no problems with it, except that the price there is usually higher than at other exchanges. For the exchanges, you usually have to register with some way of identification. This takes some time, days to 2 weeks.