Why the fuck did Satoshi implement the 1 MB blocksize limit?

[ranochigo]

Moreover, "tricking someone into a false block chain header list" requires you in any case to spend PoW on that block chain header list of the same order of magnitude than the prong you want your SPV victim to believe.  If you do that, you can just as well trick a full node into your prong.

SPV clients cannot validate the rules of the network and will hence be able to be tricked into a block with valid PoW but with differing rules from the reference clients. They are hence invalid as per full nodes which validates the full block. (I'm not talking about the merkel root part but the part which you said that nobody cares about the validity of a transaction.)

Since SPV clients blindly follow the chain with the longest valid PoW, it isn't that hard to cheat a SPV client.

No, as I outlined, that is not correct.  In order to trick me into believing that, you have to provide me with of course the fake transaction, but you also have to provide me with the leg of the Merkle tree that connects its root to the transaction.  That Merkle root is included in the block chain header list I have.

If that header list is ending on the block chain headers that mining pools are currently mining on, then I know that that transaction is a part of the very block chain miners are mining on right now.  That is exactly the same block chain that full nodes have right now also.

Again: if, of two block chains, the leading heads of the header blocks are the same, both the ENTIRE BLOCK CHAINS are identical.

No disagreements here.

So there's no such thing as a rogue SPV server, IF I can have access to the latest block headers being mined right now.  And even if I cannot have access to the latest blocks being mined (and then, my full node wouldn't get access either), that "rogue SPV server" still has to spend a lot of PoW to make the false prong.  He will have to spend as much PoW grossly as attacking the real chain, and for this attack to succeed, he must also ensure himself to avoid me of learning about the real chain (that may have somewhat more PoW).

Your client assumes the chain with the longest PoW as the correct chain. If this happens, isn't your SPV client vulnerable?

A full node is just as "vulnerable" to such an attack.

A full node is vulnerable to a 51% attack definitely. But isn't your point about a block which violates the protocol rules? If anything, that block isn't valid.

If I can know the latest headers, I cannot be tricked into accepting anything in the block chain that a full node that is accepting these latest headers, wouldn't have accepted either.

And that begs the question: How do you get the latest headers, with a certainty that it is valid.

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[Carlton Banks]

The problem is that you didn't even understand the logic of the arguments here.

Nope, you've misconstrued what they've said.  They're saying that SPV users rely on someone to give them a correct copy of the blockchain because SPV clients are not checking the history to validate if what they've received is correct.  The theoretical double spend wouldn't be in the actual blockchain that everyone else can see, it would be in the fraudulent copy being given to the SPV user.  Read what achow101 said again:

No, that is cryptographically impossible.  You cannot give a "fraudulent copy of the block chain headers" to an SPV user, if that user knows the currently actual block chain headers, in exactly the same way full nodes do.  

That isn't what he said, and you know it.

Go back and read everything. 

That isn't going to be happening, the best strategy with your posts is to skim-read them until one finds the deliberate errors you try to promote as facts

[dinofelis]

Moreover, "tricking someone into a false block chain header list" requires you in any case to spend PoW on that block chain header list of the same order of magnitude than the prong you want your SPV victim to believe.  If you do that, you can just as well trick a full node into your prong.

SPV clients cannot validate the rules of the network and will hence be able to be tricked into a block with valid PoW but with differing rules from the reference clients. They are hence invalid as per full nodes which validates the full block.

Since SPV clients blindly follow the chain with the longest valid PoW, it isn't hard to cheat a SPV client.

No, as I outlined, that is not correct.  In order to trick me into believing that, you have to provide me with of course the fake transaction, but you also have to provide me with the leg of the Merkle tree that connects its root to the transaction.  That Merkle root is included in the block chain header list I have.

If that header list is ending on the block chain headers that mining pools are currently mining on, then I know that that transaction is a part of the very block chain miners are mining on right now.  That is exactly the same block chain that full nodes have right now also.

Again: if, of two block chains, the leading heads of the header blocks are the same, both the ENTIRE BLOCK CHAINS are identical.

No disagreements here.

OK, great.

So there's no such thing as a rogue SPV server, IF I can have access to the latest block headers being mined right now.  And even if I cannot have access to the latest blocks being mined (and then, my full node wouldn't get access either), that "rogue SPV server" still has to spend a lot of PoW to make the false prong.  He will have to spend as much PoW grossly as attacking the real chain, and for this attack to succeed, he must also ensure himself to avoid me of learning about the real chain (that may have somewhat more PoW).

Your client assumes the chain with the longest PoW as the correct chain. If this happens, isn't your SPV client vulnerable?

A full node is just as "vulnerable" to such an attack.

A full node is vulnerable to a 51% attack definitely. But isn't your point about a block which violates the protocol rules? If anything, that block isn't valid.

No, it is not a 51% attack.  It is "isolating a full node network-wise, and have him swallow a (correctly mined) side prong of the actual chain".  Then you can make believe that full node that this is the correct chain - and it is A correct chain - but it is not the current consensus "out there".

However, in order to pull that feat, you have:
1) to isolate your victim network-wise
2) still to make that side prong with all the PoW that goes into it

which makes this attack highly improbable.

If I can know the latest headers, I cannot be tricked into accepting anything in the block chain that a full node that is accepting these latest headers, wouldn't have accepted either.

And that begs the question: How do you get the latest headers, with a certainty that it is valid.

The same way a full node does.  In order to provide me, SPV user, with a "false prong of block chain headers" you have to do exactly as I previously indicated:
1) isolate me network-wise so that I cannot talk to the majority miners
2) still you'd have to MAKE that false chain of headers with all the PoW that goes into it.

The ONLY difference between me, SPV client, and a full node, is that I'm not going to download the block bodies, and check the block body validity.  I take it that if miners are willing to spend a lot of PoW building on top of such blocks, that they've verified them, or that bitcoin is, as I said, broken, because the actual consensus block chain out there contains, deep down, false blocks, and miners still continue to put MAJORITY HASH RATE on top of it.

If there's a block, 6 or more blocks deep, and with majority hash rate (in fact, with no other prong around) still mining on top of it, I take it that that block is correct, or that bitcoin is broken.  In order for me to know that, I simply have to find 6 block headers on top of the block I'm considering, and I know that that hash rate has been spent on it.  If ever that block were false, it would be utmost amazing that miners are putting full hash rate on it, and are NOT mining on the "correct" side prong.

If a rogue SPV server cannot succeed in  isolating me from the network, then in order to trick me, he has to pull a full 51% attack to convince me to take his, majority POW prong, over the "real" one.  But in as much as he can pull that, he could actually attack the real block chain just as well.  And in as much as he's pulling that on top of a false block, why wouldn't he attack the real chain ?

[nullius]

dinofelis, your only discernible input on this forum is misrepresenting facts in a (kind of) subtle way. Well, you're also good at avoiding direct debunking of the things you say which aren't true.

You ought really to be banned, as it's too obvious that you're not interested in any kind of constructive debate, and never have been (unfortunately, dinofelis is likely the owner of many accounts that have been created with a suspiciously similar style of debate, only adding to the perception that the owner is very intent on wasting everyone's time on Bitcointalk.org)

This is why I enacted a policy of not arguing with him.  I directly debunk a few pieces of his worst misinformation for the benefit of others who may not know.  Then, I try to redirect the thread to its proper course—or just hurl around insults, if (as this thread) it has no proper course.

[...casting pearls before swine...]

I just realized you missed a crucial point of SPV here:

achow101 has more knowledge of Bitcoin in his toenail clippings than you do in your head.  The only thing he missed was a crucial point about that old aphorism against wrestling with pigs (you get muddy, and the pig enjoys it).  Show some respect, you blockhead.

That isn't what he said, and you know it.

Go back and read everything. 

:)

That isn't going to be happening, the best strategy with your posts is to skim-read them until one finds the deliberate errors you try to promote as facts

The best strategy is to skim for the select pieces of deliberate misinformation which are most likely to mislead newbies and learners.  That plus the anti-nodes agenda, and the parts who demonstrate craziness in the sense of severe mental defect.

[dinofelis]

This is why I enacted a policy of not arguing with him.

That would be a good thing to do.  You do not contribute anything useful in this technical discussion, which is about the security of the SPV protocol,  which in itself is a crucial element in the scalability of block chain systems, and which is related to the subject of this thread.

Your few interactions were not of any utility in the advancement of the subject, and essentially ad hominem.

As it stands, the SPV protocol is a cryptographically secure way to know whether a transaction is part of the actual consensus block chain with a very light network overhead.  The counter arguments given by achow101 and by a few others necessitates that the current bitcoin block chain contains deep down, double spends, or necessitates an attack that would also trick a full node, and that in any case, would require a huge PoW effort on the part of the attacker.

[nullius]

ad hominem

Ooh, you cribbed some Latin words from the Interwebs!  Fancy!  Too bad you know nothing of logic or rhetoric.

Like “appeal to authority”, argumentum ad hominem is only an informal fallacy; unlike formal fallacies, there are situations in which these are not fallacious at all.  For example, whereas you have repeatedly shown yourself to be willfully ignorant and ineducable, it is not a fallacy to point out that achow101 is an expert (he is) and you are a doofus (you are).  He is right.  You are wrong.  Quod erat demonstrandum.

That’s not the most rigorous proof I’ve ever made, but it’s more than you deserve.  So, get lost.

[dinofelis]

ad hominem

Ooh, you cribbed some Latin words from the Interwebs!  Fancy!  Too bad you know nothing of logic or rhetoric.

Like “appeal to authority”, argumentum ad hominem is only an informal fallacy; unlike formal fallacies, there are situations in which these are not fallacious at all.  For example, whereas you have repeatedly shown yourself to be willfully ignorant and ineducable, it is not a fallacy to point out that achow101 is an expert (he is) and you are a doofus (you are).  He is right.  You are wrong.  Quod erat demonstrandum.

That’s not the most rigorous proof I’ve ever made, but it’s more than you deserve.  So, get lost.

Appeal to authority over a cryptographic reasoning in a trustless system  

Do you have any technically and cryptographically sound arguments that may contribute anything to the discussion too ?  Up to now, you sound somewhat like the cardinals telling Galileo that he could get lost (or could get burned) because the authority, Aristotle, said that the earth didn't turn and the Pope too said that he was wrong.  That's not how science, or any rational reasoning, is done.

Do you have an argument against my essentially mathematical demonstration that the SPV system can only be fooled in those circumstances where:
1) a full node would be fooled too
or
2) the currently ongoing block chain with the highest PoW contains blocks that are false, ie. contain double spendings, but a large majority of miners nevertheless continues to build upon it ?

I indicated where achow101's answer went wrong, namely that the SPV has the block header chain, just as well as a full node has it.  He somehow thought that the SPV protocol consisted in just giving one correctly mined block independent of the block header list.  But that's not correct.  Even an SPV client gets all block HEADERS.  If one would only mine one stand alone block, yes that wouldn't be cryptographically secure, and that's essentially what achow101 tells me.  But that's not SPV.

The only thing that an SPV node doesn't do, and a full node does, is to see whether the block bodies are correct.  Miners are supposed to do that. But an SPV node cannot be tricked in believing a correctly mined block is part of the chain while it isn't, because it wouldn't fit with the header list.  
So only two possibilities remain:
1) the header list I obtained is wrong to trick me
or
2) the block is wrong (contains a double spend)

Well, if it is 1), a full  node is just as vulnerable ; and this attack is hugely expensive in PoW.
If it is 2) it means that the chain with most PoW has been mining on top of a false block since quite a while.

Hence my statement is proven.  

[RNC]

That isn't what he said, and you know it.

dinofelis, your only discernible input on this forum is misrepresenting facts in a (kind of) subtle way. Well, you're also good at avoiding direct debunking of the things you say which aren't true.

You ought really to be banned, as it's too obvious that you're not interested in any kind of constructive debate, and never have been (unfortunately, dinofelis is likely the owner of many accounts that have been created with a suspiciously similar style of debate, only adding to the perception that the owner is very intent on wasting everyone's time on Bitcointalk.org)

Are you the one they send in to abuse people and if they answer back they get banned because many of you're posts seem to be picking a fight with people not
quite seeing things your way.

That isn't going to be happening, the best strategy with your posts is to skim-read them until one finds the deliberate errors you try to promote as facts

I wonder why you have not been banned or are you in with the owners ?

[pebwindkraft]

Gentlemen! 

This is not a forum to through with mud. This behavior shows a certain level of infancy. Please respect each other. There are enough trolls in the Reddit’s, but we shouldn‘t come down to the same level here.

I fully understand that this is tough times for bitcoin and I see, that some people are really disappointed.
This doesn‘t give anyone the right to start insulting others...

There are those here in the forum, who have a high level of reputation AND KNOWLEDGE, and those who are challenging the actual view. Yes, why not? It now became a religious fight about who is wrong, and who is right. Does this make sense?

Those who got it, have left, those who are touched by the provocation are reacting angry, and only support the continuation of the nonsense.

I want to reply with Aretha:
Think !
(Before you reply)

[3yed]

That isn't what he said, and you know it.

dinofelis, your only discernible input on this forum is misrepresenting facts in a (kind of) subtle way. Well, you're also good at avoiding direct debunking of the things you say which aren't true.

You ought really to be banned, as it's too obvious that you're not interested in any kind of constructive debate, and never have been (unfortunately, dinofelis is likely the owner of many accounts that have been created with a suspiciously similar style of debate, only adding to the perception that the owner is very intent on wasting everyone's time on Bitcointalk.org)

Are you the one they send in to abuse people and if they answer back they get banned because many of you're posts seem to be picking a fight with people not
quite seeing things your way.

That isn't going to be happening, the best strategy with your posts is to skim-read them until one finds the deliberate errors you try to promote as facts

I wonder why you have not been banned or are you in with the owners ?

Definitely agreeing with you here RNC, these guys are the aggressive ones... I feel like we're all reading a different conversation, or there is some joke I'm just not getting?

I read this entire discussion, followed the links and sources cited by everyone, did more research on my own to understand the conversation a little better as it's quite meaningful.

All I see is these guys bashing on dinofelis when he/she is the only one keeping their cool, while engaging in discussion, rebuking their points, and them occasionally rebuking his, but after they do, and he replies to their point with more validation, they seem to disappear or get defensive/aggressive and bark about something different.

So, yeah, you all raised different points of which I can't comprehend all of it, but, for the most part, I learned a lot from this discussion, and seeing the negativity towards dinofelis seems pretty unfounded and unfair and completely pointless to the discussion.

As an outsider, learning about this more technical stuff, he/she is the only one that doesn't seem like an asshole. If he/she is wrong, just cite your sources and outsiders like me will side with you, not  your shitty aggressiveness.

Can any other experts please weigh in, as dino has been carrying this thread with good and meaningful discussion, not only on the technology front but the whole different perspectives/philosophies surrounding BTC.

Spurred by a good question from Anyonmous_kid that just sent me down the rabbit hole for 2 hours of reading/researching.

Now please, thank each other for allowing less technically inclined people like me to view/understand a more nuanced technology, still in it's infancy, so that we plebs can better conceptualize/visualize the whole eco-system surrounding block-chain technology/btc. 

Anyway, I literally created this account to say this because I feel that this forum is very useful and much better than reddit, and then I see assholes on here that have "legendary" status that just get away with shit-talking others but not getting modded or actually providing empirical evidence, or any research/sources other than hearsay to refute, what feels like a good discussion.

Bah, whatever, thank you, stop being mean, I really enjoy the discussion and the debate is good for us plebs, make us feel better knowing even you smarter folk have varying perspectives on this whole crypto-movement thing, just drop the attitude, it's quite pathetic and makes things confusing for us less-technically inclined people trying to decipher fact from anecdotal points of view.

[achow101]

This thread has devolved into a lot of trolling, mudslinging, and flaming. Thus it shall be locked.