They indicate that a key has been temporarily removed from the pool and then returned to the pool while an operation involving it is taking place. See the wallet.cpp file.

These functions allow multi-threading (two threads can't be using the same key at the same time).

It's not the SHA-1 it is the SHA256d. Also quite confusingly, the output bytes are reversed when displayed to the user!

The RegEx you are looking for is:

I don't think there are any test vectors. I think the best you can do is compare against bitcoinj and modify bitcoinj's tests to test your implementation.

Ignore what I said about redeem scripts. The transaction does seem to be valid but it is non-standard. The input script size is longer than 500 bytes. Eligius won't accept the transaction so you will need to contact Luke Dashjr and get him to see why Eligius is refusing to accept it.

You are trying to spend P2SH transactions and your transaction is lacking any redeem scripts so it is not valid.

So a fork occurs at some point and an exchange has to decide which fork it should take. Does the exchange owner have to contact all his customers to see which forks they are on, contact other exchanges to see what forks they are on. And what happens if some people disagree? That doesn't sound very scalable to me.

A new user will download the longest chain which meets the rules of the protocol. If the longest chain breaks the rules and mines more coins than allowed the blocks are not valid and hence do not count towards the definition of longest.


So this scheme achieves consensus via the trusted method of asking a friend. It will probably work but it won't scale.

It would make far more sense to place the panels above the road rather than under it. Above the road, they would be far cheaper to install, are out of the shade and can be angled towards the sun so far more efficient, keep cars underneath cool, keep the road surface dry and snow free and hence make the road last longer, are easier to maintain and replace without affecting road users, and can still be connected to lights embedded in the road surface or above the road.

The ideal location for solar panels is above car parks in warmer climates (southern states of the USA, southern Europe, Australia, South East Asia, Middle East) like in this image:

http://www.ereleases.com/pic/EEProCarport.jpg

Nice idea but the pool of unconfirmed transactions is not a global constant so this cannot possibly work.

Has anyone though about a decentralised burglar alarm?

People probably have thought about decentralised operating systems, but probably only people who don't know how an operating system works.

This won't protect against most attacks because transactions are easy to create. An attacker can create lots of bogus transactions to and from himself to fill up his blocks. In all cryptocurrencies both users must be on the same branch for a transaction to be seen as valid. The problem is that merchants aren't always online. When they come online they will see two forks, how will they know which is the real fork and which is the attack. Under this scheme they won't know, they will see valid transactions occurring on both forks.


How are users excluded? Surely this requires consensus, how will that consensus be achieved?

No, bitcoin transactions are push only however you can create your own systems which use bitcoin at the low level but they won't have the built in security of bitcoin.

For example the merchant scans the QR code giving the merchant computer an address of an endpoint which the computer can connect to, to make a payment protocol request. The customer authorises the app to make a payment to the address supplied in the payment request.

The program already exists: btcrecover. Use the feature to test all deleted character possibilities.

I can't work out what is wrong then. Try using btcrecover https://github.com/gurnec/btcrecover

If that doesn't work, your file has probably become corrupted and you will need an expert to have a look at it and see if it can be repaired.

No need to remove all data and blocks. Other than that those are the right steps.

OK try installing a fresh copy of bitcoin-qt.

No need to deinstall the client. Just rename your new wallet as newwallet.dat  and move a backup old wallet named wallet.dat  into the folder. Restart bitcoin-qt and you should be able to use the old password to change the password on the wallet.

Did you delete the old wallet.dat file? If not, you can use it to get your coins back and you can set a "new new password"

Were these attackers actually being dishonest (not mining on top of the chain with greatest difficulty) ? Or were they just flooding the hashing power?

The miners essentially decide (with bitcoin the rules are sort of obvious so everyone agrees to them) but with multi-pow coins miners have to rely on working out what will make them the most money/coins.  In general this means sticking with what everyone else is doing, the only practical way of knowing what everyone else is doing is assuming everyone is following the software. In theory thus, optimum strategy is to follow the software and hence the developer gets to choose.

In reality, some miners might refuse to download new updates. Now you have different miners enforcing different rules, working out the optimum in this situation is far from trivial and could lead to instability. The full economic analysis of this is very complex.