And the network knows which one was broadcast first through what mechanism exactly?

In our universe, there are limits to the speed that information can travel.  Which means that "first" is not a globally meaningful concept, only a local one.  The blockchain is an attempt to achieve a global ordering using only local information.


Bummer.

That's what you hear, but the truth is different.

When a bank makes you a loan, they just add a number to your checking account balance.  They also make a new account (your loan) and subtract a bigger number from that, so according to their books, they are even better off than before.  They don't have to run out and get more bits from someone.

When you spend part of that loan, you write checks against that new balance.  To the extent that your checks go to other banks, their account with the regional fed is decreased, which may put them in a tricky situation with the auditors, causing them to borrow to keep their reserves up.  This loan is, of course, backed by the asset they are holding, namely your promise to pay them.

Actually, lots of people get the order of events wrong with private lending.

Banks loan whenever they find a creditworthy borrower, and the money comes out of thin air at that point.  After the loan is made, if the bank's reserves are insufficient, they borrow from the fed.  This is a pull process initiated by the bank, not a push process initiated by the fed.

Congressional spending is a different story.  When congress spends, the fed creates money out of thin air and loans it to the fed.

The actual mechanisms involved are a bit more complicated.  You have a checking account with your local bank, your local bank has a checking account with the regional fed branch.  If congress writes a check to you, you present it to your bank, and the bank increases your account balance.  Your bank then presents it to the fed, which then increases your bank's account balance.  (In ordinary check clearing, the regional fed would decrement some other bank's account balance, making a zero sum.)

You can also think of it as 0x02+mod(Y,2)

Is searching really so hard?  There are dozens of threads discussing this.

First, let me say that there is no vote.  A change to the hashing system is automatically a hard fork.  If SHA weakens enough to concern us, the support for a transition will be overwhelming, so approximately everyone will follow.

Second, modern cryptosystems don't typically have sudden catastrophic breaks, they get weaker over time.  Bitcoin's design gives us even more safety margin.  MD5 is considered to be hopelessly broken, and should not be used   And yet, if mining was based on it, we'd still be fine because all of the preimage attacks require more freedom of input than bitcoin allows.

Third, an orderly transition away from SHA is certainly possible, even in the ASIC world.  In other threads on this topic, I've described one possible way to make the transition, but there are certainly others.  It would take time to happen, but, as described above, we'd have plenty of it. 

No, no, no.  Bitcoin is a set of rules, a "protocol", if you'd prefer that word.  If there is a fork, the branch that does not follow the current rules is "not-bitcoin", and "bitcoin" continues as usual.  It doesn't matter what the looters call their branch, it will be "not-bitcoin", even if not in name.

Maybe you should take Keynes's dick out of your ass and read what Adam and Ludwig have to say on the subject.

Hedging is totally different; a topic of finance, not economics.  Smith, for example, destroyed your "merely" before your great-great-great-grandmother was born.  Mises followed up with specific refutations to the rest of your bullshit a while later.

If you had actually read the article linked, you'd see that rather than being about a "general rise in the assets price", speculation is the action taken by traders that believe that some specific asset is misvalued, and their attempts to correct that specific error.  This leads to the opposite of bubbles and malinvestment.

It really isn't hard to run the blockfiles through bzip2 to see how much compression is really possible.  If I recall correctly, when I did it, I  got about 30% compression on the block files.

The code I posted needs a connection to a bitcoind node, yes.  But anyone that wants to is free to toss it on a webserver and provide the service.

I'd recommend doing it on a box that isn't also hosting a wallet.  I'm not aware of any vulnerabilities involved in passing user-provided data to the RPC interface in that context, but it may be a good idea to sanitize the inputs first.  That's kinda why I'd rather not host it on any of my servers.

I hate to interrupt your monologue, but around here the word "speculator" is usually used in the same way that one would use the word "boogeyman".

As in, "The boogeyman speculators crashed the market."

Or work on small systems, or need access to specific opcodes in a CPU.  I still do PIC stuff mostly in assembly, and not long ago I wrote a wrapper for the RDRAND instruction (in newish Intel CPUs) that used a bunch of inline assembly.

Oh, that?  Well, that is certainly easy enough.

I'm not aware of any problem that can't be solved with either C, LISP or both.  C is good when you need to think about the machine, LISP is good when you need to think about the problem.

Or, in other words, most of what most computers do most of the time is not what we would normally think of as "computation" except in a very technical sense, and C is a very good language for handling the non-computational tasks involved in, for example, an operating system.  It is also excellent if you need to do bulk computation.

LISP, on the other hand, is great for breaking down complex problems, or doing a bunch of processing.  I am occasionally sad that bitcoin scripts are not very LISP-y.  That has always struck me as another instance of Greenspun in waiting.

In real life, most of the time, I end up using PHP by default.  Since it is mainly a web programming language, it is already connected to a ton of stuff, and since it is based on C, it has access to tons of low level stuff too.  Want a daemon that accepts network socket connections, performs cryptography, talks to a database, and can email you PDFs?  Done and boring.  It is just as much a universal glue as Perl, but way less annoying, and people can actually read it.

For those not following along, /dev/urandom uses a cryptographic pseudo-random number generator when the entropy pool is depleted below the ability to satisfy a request with actual entropy.  CPRNGs are very widely used and very safe.

The weakness that gmaxwell is talking about is that since a CPRNG is deterministic (it is an algorithm that runs on a computer), someone observing a sequence of outputs from it could possibly reconstruct an output that they did not observe.  In practice, this isn't a big deal, because if anyone was in a position to observe the stream, you are already well fucked and they can probably just take your keys directly.

Also, note that he says "potentially interesting".  I'm not current on the literature, but I'm not aware of anyone actually reproducing the missing portion of a stream by using this method.  It is theoretically possible though, and maybe someone has actually done it.  Also, people are aware of the problem and take steps to make it harder.*

A genuine entropy source will provide a stream of bits that have absolutely no relationship to any other bits anywhere in the universe.  Someone watching such a stream go by will not in any way be able to recreate the part of it that you take.

In practice, it comes down to paranoia.  I side with paranoia in theory, but with reality in practice.  As in, I prefer my keys to come from sources as close as possible to actually being genuine entropy sources.  But those suck, so I use RDRAND, EGD, and other sources of high quality pseudo-entropy.  On an offline box, the difference should be negligible.

*  A weak system produces output_i from output_i-1.  A strong system produces {output_i,state_i} from hash(state_i-1).  As long as the hash function is cryptographically strong, observing the stream of output_x doesn't give enough information to recreate state or output_y.  Actual cryptographers (which I am not) undoubtedly have schemes even better than this one.

Heh, I had just hoped to point out the contradiction so that he could examine it for himself.  My confusion was rhetorical, rather than actual.

Once you see it for yourself, it becomes obvious that following law is only moral when the law is moral.  From there, you can divide out the middle step and see that on one side you have (moral = moral) and on the other side you have (law = law), with no fundamental connection between the two.  Having laws that are moral is an ideal that we must strive for.

Ghandi and MLK both wrote fairly well on the struggle to make law moral.  Letter from a Birmingham Jail is an excellent read on the topic.

I think he is asking if anyone is running a web service that can accept a hex (or whatever) bitcoin transaction string and indicate if the signature is valid or not.

I'm not aware of any sites that do that.  That doesn't mean there aren't any.

I just had to check, and it appears that the decoderawtransaction RPC command does not validate the signatures, so making such a thing isn't as simple as just slapping up a bitcoind and a couple lines of PHP.

Now and then, I start thinking that you might be confused by the polysemy of "fork".

The software can be "forked" by anyone at any time.  If their "fork" is compatible with bitcoin, then the world has two different clients for the same network.  The popularity of the two softwares will vary depending on how well they meet the needs of the users.  For now, call this #1.

If the "fork" is not compatible with bitcoin, then it is not bitcoin and the world now has two networks, each with their own client.  The popularity of these two networks will vary, depending on how well they meet the needs of their users.

The way these two networks differ depends on a choice made by the developers of the new software.  They can start fresh with a new genesis block and a new chain (#2A), or they can create a moment of divergence, where the blocks prior to that point are valid for both tines, while blocks after that are only valid for one or the other, this would be a chain "fork" (#2B).

#1 is encouraged, in a way, but difficult.
#2A is the standard scamcoin-de-jour model.  Note that no scamcoin has yet managed to develop any significant capital formation.
#2B has not yet been seen, and, as I've previously described, users of the not-bitcoin branch should expect the value of their holdings to evaporate quickly, making it unlikely to ever start.

Your last post seems to suggest that you are concerned about a #1 fork turning into a #2B fork.  It will not happen, because the gravity of bitcoin resides not in the whims of the developers, but in the economic power that has grown up around the network.  By last fall, bitcoin had grown big enough that the economic mass of the system was able to band together to hire a full time programmer, and several other people were making a decent living off of donations for their contributions.  Who knows where we will be by next fall...

Bitcoin the software project can live or die without consequence, but Bitcoin the network is probably self-sustaining and immortal at this point.

If aliens cut the planet in half, we'll have bigger problems.

Considering the relatively low amount of network traffic needed to move blocks around, that is about the most likely scenario.  No other network severing would be complete enough to cause those problems.

I haven't upgraded to 0.8 on my development box yet, so I haven't had a need to peer into the new block files.  Are they the same format as the old ones, just smaller, or did they get changed?