Wrapping your head around Bitcoin (a guide)

[hazek]

Correct me if this is wrong

Yeah you are wrong and I already explained it to you how.

[DannyHamilton]

- SNIP -
Correct me if this is wrong
 - SNIP -

You are mistaken.

- SNIP -
and then alter the mining software with my new checkpoints.  Also altering the mining software such that I ignore any information coming from the REAL miners with the CORRECT block chain.  Then I become a miner with 51% of the network.
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You need to convince EVERY user on the network to use your altered software instead of the correct software with the original checkpoints.  If you don't then they will all ignore your blockchain no matter how "long" it is.

(I should also note that it would take just minutes to solve every block since the genesis block in an offline fashion, if I am creating this alternate blockchain, since I am not in competition with anyone, and the difficulty would be minimal.)

When people say the "longest" block chain wins, they are speaking metaphorically.  The mining AND client software actually choose the blockchain with the highest total difficulty.  Under normal circumstances this happens to be the longest one, but under the special circumstances you are describing having the most blocks wouldn't qualify your blockchain.

[jerfelix]

- SNIP -
Correct me if this is wrong
 - SNIP -

You are mistaken.

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and then alter the mining software with my new checkpoints.  Also altering the mining software such that I ignore any information coming from the REAL miners with the CORRECT block chain.  Then I become a miner with 51% of the network.
 - SNIP -

You need to convince EVERY user on the network to use your altered software instead of the correct software with the original checkpoints.  If you don't then they will all ignore your blockchain no matter how "long" it is.

(I should also note that it would take just minutes to solve every block since the genesis block in an offline fashion, if I am creating this alternate blockchain, since I am not in competition with anyone, and the difficulty would be minimal.)

When people say the "longest" block chain wins, they are speaking metaphorically.  The mining AND client software actually choose the blockchain with the highest total difficulty.  Under normal circumstances this happens to be the longest one, but under the special circumstances you are describing having the most blocks wouldn't qualify your blockchain.

But if I own 51% or 85% or 99% of the network, and have modified the Bitcoin software such that every new download doesn't care about these rules of which you speak, it doesn't matter that there's this tiny faction of miners that still believe that they have the "right" blockchain.

[DannyHamilton]

. . . But if I own 51% or 85% or 99% of the network, and have modified the Bitcoin software such that every new download doesn't care about these rules of which you speak, it doesn't matter that there's this tiny faction of miners that still believe that they have the "right" blockchain.

Good luck modifying the bitcoin software that I am running such that it doesn't care about these rules of which I speak, or the bitcoin software that Gavin is running, or the bitcoin software that hazek is running, or a whole lot of other people.  Are you going to sneak into all of our houses and replace all of our software one by one while we are sleeping?  As soon as you strat trying to convince people to user "your" version of the software, don't you think people will spread the word that yours has been modified to increase the likelihood of an attack?

[jerfelix]

. . . But if I own 51% or 85% or 99% of the network, and have modified the Bitcoin software such that every new download doesn't care about these rules of which you speak, it doesn't matter that there's this tiny faction of miners that still believe that they have the "right" blockchain.

Good luck modifying the bitcoin software that I am running such that it doesn't care about these rules of which I speak, or the bitcoin software that Gavin is running, or the bitcoin software that hazek is running, or a whole lot of other people.  Are you going to sneak into all of our houses and replace all of our software one by one while we are sleeping?  As soon as you strat trying to convince people to user "your" version of the software, don't you think people will spread the word that yours has been modified to increase the likelihood of an attack?

So you, Gavin, Hazek and a whole lot of other people will end up with your own little private network with your private bitcoin economy, claiming adamantly to anyone who will listen that "we have the real Bitcoins". 

Meanwhile the US Government, in conjunction with the blessing of the UN and the G20 have sanctioned Bitcoin with the "new blockchain to be fair to all", reversing all past transactions, legislating that Sourceforge host their newly revised, CIA-approved version, and declaring the "new blockchain" as the one backed by the "full faith and credit of all the major countries of the world".

Yeah, you're right within the scope of your little world, that no one will "reverse" your transactions in your little world.  But it is absolutely, positively incorrect to claim that it is mathematical certainty that transactions cannot be reversed.  Because they can be.

Mathematical certainty has a specific meaning, and this is not within the realm of impossibility, despite how improbable it is.

[DannyHamilton]

Mathematical certainty has a specific meaning, and this is not within the realm of impossibility, despite how improbable it is.

I never argued that this is not within the realm of impossibility, only that some of your specific examples of how it could be accomplished aren't possible.  Keeping in mind that you are the one who decided this should be a discussion on semantics, I would certainly agree with you that saying a bitcoin transaction is irreversible doesn't meet a generally accepted definition of "mathematical certainty" today. However, I would also maintain that your example of a modified client also doesn't meet a generally accepted definition of "bitcoin" today.

[BlackBison]

Good write up.

Horrible colours used though. Can you please do a plain black/grey on white background please so I can hand a few of these out? Grey background sucks!

Apart from that great job! 

[QuantumQrack]

"National currencies are used because they are used."

Correct me if I am wrong but isn't this a tautology?  It doesn't have much meaning.

The quote above is poorly written.  I wouldn't want a newcomer to bitcoin to see that.  (especially if they are well educated).

[jerfelix]

Well, I was just trying to give feedback to the document that many people (myself included) feel that the words "mathematical certainty" are not appropriate.  It's feedback - take it or leave it.

Here's what Hazek's text says:

all confirmed Bitcoin transactions are with mathematical certainty irreversible, all
bitcoins are with mathematical certainty non-counterfeitable

Hazek's response was:

Btw mathematical certainty in my guide primarily refers to the ability to fake obeying the rules. It's true it doesn't account for an attacker obeying the rules and still defrauding people, but it's a fact that rules in Bitcoin must be obeyed, even by an attacker and this is mathematically certain.


And I walked through a complete example (and was accused at various steps in the process that I was wrong) where if someone doesn't "obey the rules" of Bitcoin, his statement falls apart.  

Defending the statement by saying "oh, I meant if you follow the rules" is like saying there are absolutely zero law breakers in New York City, and then saying "Oh, I meant I was only counting the ones who follow the rules."

--

Overall, I think it's a great intro.  I was just giving honest feedback about how I, and others, react to the "mathematical certainty" lines that come from Roger Ver and others, including this text. 

[DannyHamilton]

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And I walked through a complete example (and was accused at various steps in the process that I was wrong) where if someone doesn't "obey the rules" of Bitcoin, his statement falls apart.  

Defending the statement by saying "oh, I meant if you follow the rules" is like saying there are absolutely zero law breakers in New York City, and then saying "Oh, I meant I was only counting the ones who follow the rules."
 - SNIP -

You are either not paying attention, or are intentionally trolling.  Either way, I give up.

[cbeast]

Meanwhile the US Government, in conjunction with the blessing of the UN and the G20 have sanctioned Bitcoin with the "new blockchain to be fair to all", reversing all past transactions, legislating that Sourceforge host their newly revised, CIA-approved version, and declaring the "new blockchain" as the one backed by the "full faith and credit of all the major countries of the world".

Ah, the old New World Order attack argument. Yeah, if the entire world falls under a single dictator and the people refuse to revolt, then we have more problems than what we use to buy our groceries. I just don't see this this happening without a lot of objections.

[casascius]

If I could give one suggestion, I would avoid referring to the reader as a "layman" or indicate that "big letters" are needed to convey important points.

This document looks like an EXCELLENT outline for some sort of video, illustration, or document that helps convey Bitcoin to everyday people, but my take is that this itself isn't that document.

The title, "Wrapping your head around Bitcoin", doesn't particularly suggest that it's meant to help the average person understand Bitcoin - it actually suggests that it's meant to help super smart people understand it, causing the intended audience to perhaps self-select out of thinking it's meant for them.  I'd suggest "The Basics of Bitcoin: The What and The Why" or something like that.

[jerfelix]

Meanwhile the US Government, in conjunction with the blessing of the UN and the G20 have sanctioned Bitcoin with the "new blockchain to be fair to all", reversing all past transactions, legislating that Sourceforge host their newly revised, CIA-approved version, and declaring the "new blockchain" as the one backed by the "full faith and credit of all the major countries of the world".

Ah, the old New World Order attack argument. Yeah, if the entire world falls under a single dictator and the people refuse to revolt, then we have more problems than what we use to buy our groceries. I just don't see this this happening without a lot of objections.

I hope you understand that my comment was a point to prove that it was possible, not likely.  It is addressing the words "mathematical impossibility".

But yes, I agree with you... I don't see this happening without a lot of objections either.  But stranger things have happened.

[hazek]

Horrible colours used though. Can you please do a plain black/grey on white background please so I can hand a few of these out? Grey background sucks!

Sure, here you go: https://docs.google.com/file/d/0B6bqlVfJOOWsY2NGSGRiYkNaUkk/edit?usp=sharing

Good write up.

Apart from that great job! 

Thanks!

[hazek]

Meanwhile the US Government, in conjunction with the blessing of the UN and the G20 have sanctioned Bitcoin with the "new blockchain to be fair to all", reversing all past transactions, legislating that Sourceforge host their newly revised, CIA-approved version, and declaring the "new blockchain" as the one backed by the "full faith and credit of all the major countries of the world".

Ah, the old New World Order attack argument. Yeah, if the entire world falls under a single dictator and the people refuse to revolt, then we have more problems than what we use to buy our groceries. I just don't see this this happening without a lot of objections.

I hope you understand that my comment was a point to prove that it was possible, not likely.  It is addressing the words "mathematical impossibility".

But yes, I agree with you... I don't see this happening without a lot of objections either.  But stranger things have happened.

SECURITY - all confirmed Bitcoin transactions are with mathematical certainty irreversible, all
bitcoins are with mathematical certainty non-counterfeitable

Let me see if I can explain the above to you so you'll understand why it is correct.

First off all, you are wrong with your follow rules analogy:

Defending the statement by saying "oh, I meant if you follow the rules" is like saying there are absolutely zero law breakers in New York City, and then saying "Oh, I meant I was only counting the ones who follow the rules."

The only way to attack Bitcoin is to follow it's rules. The problem is not that Bitcoin rules can be broken. They can't be because you'd need to convince everyone to change to a different Bitcoin client with different rules for that. What can happen though is that the Bitcoin rules can be abused. So yes, when talking about attackers I of course mean only those who follow the rules. Those who don't simply get ignored by the network.

The problem is someone can follow the rules in such a way that can cause damage. But the damage they can cause is limited. For instance they can't steal your bitcoins, that is mathematically certain, they'd need your private keys for that. They can't reverse your transaction that contains a signature with your private key when you sent it, that is mathematically certain.

What they can do however is they can double spend any coins they themselves sent to you and this is mathematically certain, and they can unconfirm transactions up to the hardcoded checkpoint and that is also mathematically certain.



As you can see, what I say about Bitcoin security is not false. Not even by a little. Everything in Bitcoin is mathematically certain except I didn't mention the unlikely event where someone decides to abuse mathematically certainty to double spend or unconfirm transaction up to a point.

[hazek]

If I could give one suggestion, I would avoid referring to the reader as a "layman" or indicate that "big letters" are needed to convey important points.

This document looks like an EXCELLENT outline for some sort of video, illustration, or document that helps convey Bitcoin to everyday people, but my take is that this itself isn't that document.

The title, "Wrapping your head around Bitcoin", doesn't particularly suggest that it's meant to help the average person understand Bitcoin - it actually suggests that it's meant to help super smart people understand it, causing the intended audience to perhaps self-select out of thinking it's meant for them.  I'd suggest "The Basics of Bitcoin: The What and The Why" or something like that.

I appreciate the input and you're more than welcome to take what I wrote and modify it. And yes I was toying around with the idea of making this into a video but I'm a noob when it comes to that so I'd need someone who knows animation and can do voice acting to help me.

[jerfelix]

The only way to attack Bitcoin is to follow it's rules. The problem is not that Bitcoin rules can be broken. They can't be because you'd need to convince everyone to change to a different Bitcoin client with different rules for that.

Our whole point of disagreement seems to be centered around this one statement.  You seem to believe that it is absolutely 100% impossible "to convince everyone to change to a different Bitcoin client with different rules", and I don't.  Difficult?  Absolutely.  Darn near impossible?  Yup.  Do I think it will ever happen?  Nope?  Am I a firm believer in the mathematics of Bitcoin, yup.  

But, impossible?  Nope.  In fact, I don't even believe it needs to be "everyone".  But for the sake of argument, say everyone.  I believe that it would be possible through legislation, port blocking, and other evil tricks (both technological and political / legal) for the governments of the world to render the current Bitcoin client useless.  I think you are kidding yourself if you think otherwise.

Or without even convincing ANYONE to "use a different client", if a major entity / government created a new block chain with a higher difficulty level, diverting all the mined bitcoins since the last check point to them, and then performed a worldwide Black Out, to knock out the internet and Bitcoin, and when worldwide power got restored one city at a time, and one-by-one, as people were connecting to the internet, and discovering a new block chain with a higher difficulty, they'd reject their existing block chain dating back to the last check point, and boom, the deed would be done - tons of transactions reversed.  Do I think this will happen?  Nope.  Do I think it is possible?  absolutely.  

In fact, I think that it is still very much within the realm of the budget of the US Government to undo a day's worth of transactions, and probably many more.

Don't get me wrong, I have a ton invested in the success of Bitcoin.  I just believe that you lose credibility when you toss around words like impossible and mathematical certainty, when they fall just short of that 100% number.  99.9% with 300 9's after the decimal ISN'T 100%.  Sorry.

We should probably agree to disagree on this one.  I like your document, but I am just trying to explain my reaction.  It's your document - you asked for feedback, I didn't mean any offense.  Just providing feedback, and trying to explain what I meant.

[hazek]

The only way to attack Bitcoin is to follow it's rules. The problem is not that Bitcoin rules can be broken. They can't be because you'd need to convince everyone to change to a different Bitcoin client with different rules for that.

Our whole point of disagreement seems to be centered around this one statement.  You seem to believe that it is absolutely 100% impossible "to convince everyone to change to a different Bitcoin client with different rules", and I don't.

I don't either.

I specifically say this in the guide. So we're not talking about changing rules, we're talking about following rules where whether or not they are or aren't followed can be determined with mathematical certainty.

[Maciek]

I'm asking the forum experts about "is there an easy explanation of how Bitcoin works? A video maybe?"
The problem is solved I guess. There is a lot of good work done in this topic:
https://bitcointalk.org/index.php?topic=144642

I've used some ideas of @hazek and @Korbman there - and I received nice answers.

[BlackBison]

Thanks Hazek for that.