Bitstamp issued a statement two days ago on their suspending Bitcoin withdrawals:

"Bitcoin withdrawal and deposit processing will be suspended temporarily until a software fix is issued. ... We will communicate any further developments regarding this issue."

No date was given for a fix. No alternative way to withdraw was given. Two days later, there's no new announcement. Not good. That's Mt. Gox type behavior. When Bloomberg writes a story about a failure like that, the company has to fix the problem very fast, or be lumped in with other failed and failing exchanges.

This is what's called a "wireless mesh network".  It's been done before. Dewayne Hendricks used to have a company called "Tetherless Access" which, about 20 years ago, was going to build distributed radio networks something like this. He turned out to be all talk and no hardware. Then in the mid-1990s there was Ricochet Networks, which put little repeater nodes on street lights.  These standalone units forwarded packets until they reached a station with a wired connection to the Internet. Worked in the 900 MHz band. That worked fine, and was deployed in several cities.  I used to use their system.  You could get internet access at about 15Kb/s, later upgraded to about 50Kb/s.  So that went out when DSL came in.

More recently, there's Freifunk, a low-cost wireless network for rural areas being used in Zaire.

The basic problems are this:

- To get much range, at least one end of each link must have a decent antenna, up high in clear space and aimed in the right direction. It's better if both ends do. Building networks this way in rural areas works fine, if you can get line of sight to the next station.
- Short-range ad-hoc wireless mesh networks have been successful, but they need a lot of nodes in a small area. There are WiFi booster systems which network in this way.  That works fine, too.
- What doesn't work are sparsely distributed indoor antenna devices.

Now, doing this in a lower band might work, but would take more RF power than Part 15 gear.

The biggest headache is simply antenna location. If you can get people to put a whip antenna on their roof, this can work.

Just set it up so only one coin is generated, ever, and subdivide from there.

Useful information to keep in mind:

- Good-quality pictures of Mark Karpeles exist, should he be wanted by police.
- He has been recently sighted leaving the Mt. Gox offices, so he's still in Japan.
- Japan is an island chain.  It's hard to leave Japan without passing through a checkpoint.

And they need to get a real address in the US, not the same drop box place Tradehill used.

Exactly what is the proper, unforgeable way to determine if two transactions are really the same transaction? A match on inputs and outputs, first reduced to a canonical sorted form?

27MHz is still used for some industrial radio control. There's been some interest from the quadrotor crowd, who want more range, but they seem to be using 35MHz instead. The only big problem with 27MHz seems to be spillover from CB.

The receiver should probably just suck up the whole band and receive all the channels simultaneously, looking for packets of interest. Then no configuration is necessary. That will require a software-defined radio, but there are cheap chips for that now. There are boards available, but they usually won't go as low as 27MHz, because they're intended for cable TV.

The problem with all this is that it will take a reasonably good antenna to have any range, and nobody will put up big antennas any more.


         

Not any more.  That just changed in the QT client.

It looks like it's going to be necessary to wait for confirmations on your own change from now on.

Having many unspent outputs in a wallet helps speed up spends, but transactions get bigger, as they contain more inputs. This may accelerate dust generation, if there's a bias in favor of never consolidating inputs. Wallets may have to become smarter about when to divide and when to consolidate inputs. The optimal strategy depends on the wallet owner's spending pattern.

This is most likely to be a problem for a commercial wallet with high traffic, such as an exchange's hot wallet.  This could impose a limit on outgoing transaction volume. (I almost hate to suggest this, because some inept exchange may use it as an excuse for withdrawal delays.)

The original post is well written. There's another problem with the fix, though. If you can't spend unconfirmed change arising from confirmed inputs, once you've spent some money, you sometimes can't spend again until a few confirmations have been processed. There's now an option in the official QT client to enforce that rule. 

This creates operational problems for Bitcoin use. Once you've spent some Bitcoins, you may not be able to spend any more Bitcoins for tens of minutes. Whether or not you can spend depends on the denominations of Bitcoins currently in your wallet. You don't have an "account balance", you have a collection of Bitcoin items with varying denominations, and this now matters.  Explaining this to end users is going to be a problem, especially since the current user interface doesn't expose that level of detail to the user. With the "no spending unconfirmed change" rule enforced, it's going to look like this, I think:

User has 1 BTC, 0 unconfirmed, 1.0 available for spending. The 1 BTC is from a single transaction.
User spends 0.5 BTC.
User now has 0.5 BTC, 0.5 unconfirmed, 0 available for spending.
Half an hour later....
User now has 0.5 BTC, 0 unconfirmed, 0.5 available for spending.

This is not going to play well at the mall.

For a big operation with a lot of outgoing transactions, like an exchange, wallet systems may have to have something like active currency management. (This is the "we have too many twenties, and not enough fives right now" problem a retailer sometimes faces).

Anybody thinking about this?

Yes, although "spend unconfirmed change" is ON by default, so the fix is ineffective by default. That probably should become OFF in a later release.

"Bitcoin Foundation Blames Mt. Gox ‘Unpreparedness’ for Downtime"

"The Bitcoin Foundation said the Mt. Gox Bitcoin exchange in Tokyo is to blame for technical faults that prevented customer withdrawals of the virtual currency that lost as much as 21 percent of its value today. "

The financial press isn't buying Mt. Gox's excuses.

That's funny. They kept Mt. Gox in the price index when it was 15-20% above everybody else. But as soon as Mt. Gox dropped below everybody else, it's out.

One of the China-based indexes did that, too. The effect has been to pump the price of Bitcoin for months.

Oh, there will be news. Friday, most of the world's financial press covered Mt. Gox's announcement that they were suspending all withdrawals and would have a new announcement Monday. Press coverage of this was very negative. Tomorrow morning, all those news outlets will have a follow-up story. Mt. Gox is going to have worldwide press coverage again and it's going to be worse than Friday.

Well, as of 5 PM Monday Tokyo time, there's no new announcement from Mt. Gox.

This has to be fake. A real lawyer is expected to identify themself in legal advertising. ABA rules of professional ethics, Rule EC 2-9 (Legal advertising):
"Accordingly, a lawyer in private practice should practice only under his own name, the name of a lawyer employing him, a designation containing the name of one or more of the lawyers practicing in a partnership, or, if permitted by law, the name of a professional corporation which should be clearly designated as such."

No announcement from Mt. Gox, and it's midafternoon on Monday in Tokyo. No surprise there for those of us who have been following Mt. Gox.

This time it's going to be different. Bitcoin is too visible now. The stories aren't just in Coinbase and Wired any more.  When Mt. Gox stopped withdrawals on Friday, it was covered in the financial press as a major financial company in trouble.  There were stories in Bloomberg, the Wall Street Journal, the South China Morning Post, Sydney Morning Herald, Reuters, Nikkei, and even Russia Today.

The South China Morning Post (Hong Kong) reporter writes "All eyes will be focused on Japan-based Mt Gox – due to release a trading statement later today." Monday in the Western world, there will be more stories, and if Mt. Gox doesn't have some very good answers, they are going to be very negative.

There is a claim on Reddit that the Mt. Gox wallet program has a bug. The claim is that the signature algorithm is adding extra junk zeroes to signatures, which are ignored by some, but not all, clients. These provide the opportunity for a third party to modify the transaction by removing the junk zeroes, resulting in a valid transaction with a new transaction ID, which Mt. Gox's wallet does not recognize as its own. This allows spending Bitcoins sent by Mt. Gox, while Mt. Gox's own accounting treats the transaction as failed.

This is a checkable claim. If it's true, there should be such broken transactions in Mt. Gox's transaction list. Are there?

Also, this fix is supposed to fix the problem. But it takes bytes off the end of the signature string, not the beginning.  Is that valid?

This claim of a bug is checkable. Someone should check the block chain for transactions with junk pad bytes at the end of signatures, and note the ones from a Mt. Gox address.

He's just posting a garbled rewrite of this post on Reddit.