The consensus dead end.

[BlackHatCoiner]

Since 2009, some consensus rules have been added, for example SegWit. It surely does good, it's a solution for the block size limit, but I want to know how did that occur. In wikipedia it says that SegWit was activated on block 477120, but who begun that? Changes on consensus rules, as good as they are, are changes. If the majority of its users, change a consensus rule, they immediately stop being the majority. The follow their "Bitcoin".

The forum itself says on a quote that miners don't vote on changing consensus rules, only the order of the transactions. Seeing a change like that makes me wonder what else can the developers change. Should they have an impact on bitcoin? Whether if it's for good reason or not.

How did miners accept that change? They were not forced to update their bitcoin client.

-But why did you enter that title?
Well, I'm a little afraid of bitcoin's future and thus, my funds'. On the long term, one of these may occur:

• Public key to private key reversal. (I've heard that it may be possible to do that with quantum computing and pollards kangaroo method)
• Finding collisions for RIPEMD-160 hashes. Are we sure that 2¹⁶⁰ is strong enough? What if it becomes weak in the next 20-30 years?

Even if the first one can be faced pretty easily by simply creating outputs on addresses that have never spent, the second one requires consensus change. I don't know what they can change in that case, probably use of stronger cryptography, but they will have to change something! Otherwise, bitcoin will be useless. Changing a consensus rule, that important, would sour lots of people. And that's because that moment, the developers would have to "touch" people's money. It'd be a consensus dead end.

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[ranochigo]

In wikipedia it says that SegWit was activated on block 477120, but who begun that?

Segwit actually had a bunch of activation periods where miners are supposed to signal for the acceptance of Segwit and if the threshold of 95% is reached, then the rule would be activated 2 periods down. It was started after one of the difficulty periods and its support was implemented after 0.13.1.

The forum itself says on a quote that miners don't vote on changing consensus rules, only the order of the transactions. Seeing a change like that makes me wonder what else can the developers change. Should they have an impact on bitcoin? Whether if it's for good reason or not.

How did miners accept that change? They were not forced to update their bitcoin client.

See UASF (BIP148) and BIP91 with the reduced threshold. Bitcoin users are as important as miners; if you don't follow the users, then you're just mining on your own fork and the users are using another version which gives you zero economical benefits.

Even if the first one can be faced pretty easily by simply creating outputs on addresses that have never spent, the second one requires consensus change. I don't know what they can change in that case, probably use of stronger cryptography, but they will have to change something! Otherwise, bitcoin will be useless. Changing a consensus rule, that important, would sour lots of people. And that's because that moment, the developers would have to "touch" people's money. It'd be a consensus dead end.

Segwit was a controversial change with differing opinions from different camps and that's why you have BCH. If it's something that puts the network (both users and miners alike) at risk, I can't see how they would oppose such a change.

[Charles-Tim]

It surely does good, it's a solution for the block size limit,

Segwit makes use of weight to reduce transaction fee.

Possibly because of the vbytes metric, it is a common misconception that segwit somehow makes transactions much smaller—but this is incorrect. A 300-byte transaction is 300 bytes on-disk and over-the-wire. Segwit just counts those bytes differently toward the maximum block size of 4M weight units.

The maximum size of a block in bytes is nearly equal in number to the maximum amount of block weight units, so 4M weight units allows a block of almost 4M bytes (4MB). This is not a somehow "made-up" size; the maximum block size is really almost 4MB on-disk and over-the-wire. However, this maximum can only be reached if the block is full of very weirdly-formatted transactions, so it should not usually be seen.

The typical size of a block depends on the make-up of transactions in that block. As of 2017, the average transaction make-up would lead to blocks with 4M weight units being about 2.3MB in size if all transactions were segwit transactions.

In wikipedia it says that SegWit was activated on block 477120, but who begun that?

I do not know much about consensus, experienced members about it will answer that. But what I know is that segwit transaction begins with miners supporting it activation, while majority supported it and makes the activation successful.

Public key to private key reversal. (I've heard that it may be possible to do that with quantum computing and pollards kangaroo method)

Private key can not be reversed as it is a one way function. But you meant can it be brute forced through the use of quantum computing. According to what I learned, it is not early days quantum computers that can brute force the ECDSA, it will take time before this can happen, and before it will happen, there would have being layers of protection against quantum computing to brute-force bitcoin private key from public key.

Finding collisions for RIPEMD-160 hashes. Are we sure that 2160 is strong enough? What if it becomes weak in the next 20-30 years?

Double hash/hash160 is used in a one-way-function to generate addresses from public key, it will be much harder for quantum computing to brute force private key from addresses. And know if this wants to become possible, before it becomes possible, there will be another layer added that will be impossible for quantum computing not to brute force the private key.

[aliashraf]

FYI: Segwit was not a consensus change, rather it was a consensus expansion, legacy pre-Segwit full nodes could continue confirming and not forking off the legacy chain, nobody is able to touch one Satoshi of legacy wallets ever.

It was enforced by a User Activated Soft Fork, UASF i.e. forced by a majority of user wallets that adopted the soft fork, miners followed this majurity. It is called soft fork because its backward compatibility helped not to mandate a simultaneous global upgrade, letting nodes to adopt the feature whenever they wish to use it; it is user-activated because in the special circumstance that the upgrade was going to take place the community was undergoing a scaling debate which ended to bch hard fork and some mining pools were acting suspiciously.

I do agree that UASFs are not a perfect solution and shouldn't be weaponized by devs to do whatever they wish, but because of the centralized situation in the Bitcoin mining scene, we need such a measure to keep large pools inline.

[BlackHatCoiner]

Segwit actually had a bunch of activation periods where miners are supposed to signal for the acceptance of Segwit and if the threshold of 95% is reached, then the rule would be activated 2 periods down. It was started after one of the difficulty periods and its support was implemented after 0.13.1.

Threshold of what? Of nodes? How can you know the percent of nodes that agree with the new rule?

See UASF (BIP148) and BIP91 with the reduced threshold. Bitcoin users are as important as miners; if you don't follow the users, then you're just mining on your own fork and the users are using another version which gives you zero economical benefits.

There are nodes. Bitcoin miners are bitcoin users. Every person that runs his own node, is a user. Indirectly, a person that runs an SPV node is also a user that trusts other nodes' information. The users are those who follow the consensus rules, the ones Satoshi had chosen. A change on a consensus rule confuses the people of what is the real bitcoin.

I do not know much about consensus, experienced members about it will answer that. But what I know is that segwit transaction begins with miners supporting it activation, while majority supported it and makes the activation successful.

But this is not a majority decision. It's a consensus rule. Everyone is free to change any consensus rule they wish to, but they won't have Bitcoin. They'll have their own coin. If the majority wants 42 million coins, they're free to re-create bitcoin. They're free to leave it, but they can't announce it as the new "Bitcoin".

Private key can not be reversed as it is a one way function. But you meant can it be brute forced through the use of quantum computing. According to what I learned, it is not early days quantum computers that can brute force the ECDSA, it will take time before this can happen, and before it will happen, there would have being layers of protection against quantum computing to brute-force bitcoin private key from public key.

Actually ECDSA is indeed reversible. It's just currently infeasible. Hash functions such as "SHA-256" and "RIPEMD-160" are irreversible/one-way.

And know if this wants to become possible, before it becomes possible, there will be another layer added that will be impossible for quantum computing not to brute force the private key.

There will be ways to prevent attacks from quantum computers. The question is how they'll force every node to accept them.

[ranochigo]

Threshold of what? Of nodes? How can you know the percent of nodes that agree with the new rule?

Percentage of blocks, Miners Activated Soft Fork.

The users are those who follow the consensus rules, the ones Satoshi had chosen. A change on a consensus rule confuses the people of what is the real bitcoin.

I disagree. I think users should have the freedom to choose what is defined as Bitcoin. You don't use Bitcoin just because Satoshi said so; you use Bitcoin because you stand with the rules that governs it (21mil coins, non-reversibility, etc). Having a fork such as the one that you have described would definitely not be unpopular but people can just continue on the fork that doesn't implement the fix like how Bitcoin Cash is formed.

There will be ways to prevent attacks from quantum computers. The question is how they'll force every node to accept them.

You don't have to. If you don't want to implement the fix or to not burn the old coins, then an altcoin would be forked from that, just like how ETH and ETC came about.

[BlackHatCoiner]

I disagree. I think users should have the freedom to choose what is defined as Bitcoin. You don't use Bitcoin just because Satoshi said so; you use Bitcoin because you stand with the rules that governs it (21mil coins, non-reversibility, etc). Having a fork such as the one that you have described would definitely not be unpopular but people can just continue on the fork that doesn't implement the fix like how Bitcoin Cash is formed.

It seems that it's just my opinion, but I don't believe that users should have the freedom to choose what is defined as Bitcoin. They have the freedom to experiment with it, to use it, to create new things on top of it, but not to change it. Satoshi chose these consensus rules and every person who refuses to accept them is free to follow a different chain.

As for Satoshi:  It's not the fact that a "guy" decided what rules should be followed. That doesn't sound good. It's just the way the chain started. Every consensus change would be against the philosophy.

[ranochigo]

It seems that it's just my opinion, but I don't believe that users should have the freedom to choose what is defined as Bitcoin. They have the freedom to experiment with it, to use it, to create new things on top of it, but not to change it. Satoshi chose these consensus rules and every person who refuses to accept them is free to follow a different chain.

Satoshi chose 1MB as the block size limit (before there wasn't any limits) but look, it is obviously not feasible if we need to scale up. If you only consider the original consensus rules to be the only version of Bitcoin, then you would probably not be using the Bitcoin that you have today. Satoshi did lay the groundwork but it is obvious that not all of the choices that he made has actually made any sense at all.

As for Satoshi:  It's not the fact that a "guy" decided what rules should be followed. That doesn't sound good. It's just the way the chain started. Every consensus change would be against the philosophy.

Would it have made sense to be following the original Bitcoin with no block limits, an overflow bug, no segwit, no p2sh, etc? It was obvious that Satoshi didn't mean to leave Bitcoin as it is, there is a set of rules which probably won't garner any support or would redefine Bitcoin but it doesn't mean you can't improve Bitcoin.

I don't think this is really up for discussion, I don't think Bitcoin would've survived if it didn't evolve.

[BrewMaster]

FYI: Segwit was not a consensus change, rather it was a consensus expansion, legacy pre-Segwit full nodes could continue confirming and not forking off the legacy chain, nobody is able to touch one Satoshi of legacy wallets ever.

since SegWit did change some of the old consensus rules it is also a consensus change too. but since all the changes are backward compatible, that made the fork a soft fork.
one consensus rule that it changed for example was the dummy stack element for OP_CHECKMULTISIG that can no longer be anything except OP_0.

[aliashraf]

FYI: Segwit was not a consensus change, rather it was a consensus as , legacy pre-Segwit full nodes could continue confirming and not forking off the legacy chain, nobody is able to touch one Satoshi of legacy wallets ever.

since SegWit did change some of the old consensus rules it is also a consensus change too. but since all the changes are backward compatible, that made the fork a soft fork.
one consensus rule that it changed for example was the dummy stack element for OP_CHECKMULTISIG that can no longer be anything except OP_0.

The sole fact of backward compatibility is enough to refute any claim about "consensus change". For the muliltisig opcode,  current Bitcoin supports old UTXOs with legacy format but doesn't allow new txns with such a format to be included in the blockchain anymore.

The point is what OP is worried about,  his assets being subject to uncertainty due to events like Segwit UASF, is absolutely void.

[BrewMaster]

The sole fact of backward compatibility is enough to refute any claim about "consensus change". For the muliltisig opcode,  current Bitcoin supports old UTXOs with legacy format but doesn't allow new txns with such a format to be included in the blockchain anymore.

The point is what OP is worried about,  his assets being subject to uncertainty due to events like Segwit UASF, is absolutely void.

that's true but SegWit is still a lot of change in consensus rules not just simple expansions.

OP's concerns are mostly because he is comparing an upgrade like SegWit with a mandatory change that would for example remove RIPEMD160 from the protocol. if it is proven that RIPEMD is indeed weak then the change won't be as hard as any others before.

[BlackHatCoiner]

Possible doesn't mean it's probable.

I agree with you, don't get me wrong. I am very sure that it's nearly impossible to reverse a public key to private, I'm talking theoretically, what would happen in that case. It may be in 2040, or in 2140, but there will be sooner or later a year in which quantum computers or any other advanced technological creation constitutes a threat to the current hashing algorithms.

Let's hope SHA-256 is still strong enough in the next 20-30 years.

RIPEMD-160 is the one we should hope for. It's 2⁹⁶ times "weaker" than SHA-256.

The term "real bitcoin" is ambiguous, what defines it?

True, it's ambiguous. But I don't blame that they'll change the "real bitcoin", neither that they'll increase the 21 million limit. I'm in favor of the bitcoin's principles, I'm just wondering how can they make such change. A bitcoin node should be running forever if possible. But any node that'd do that since 2009, would not follow the correct chain at the moment. The current chain would be considered invalid due to SegWit.

My conclusion is that the developers won't force you directly. But they will.

[pooya87]

the USER ACTIVATED SOFT FORK was done by node banning those that disagreed. this pretty much turned a network of 45% (4500 of 10000) into a 100%(4500 of 4500) vote to cause the activation.

UASF nodes didn't ban other nodes, they rejected blocks. And the way I remember it their number was nowhere near 45%, I think you are confusing the hashrate signalling for SegWit with UASF nodes. Nodes signalling for BIP148 were barely 10% of the total nodes, the total was also no 10k it was closer to 200k.

yep april-july2017 only had 45% flag in favour. then suddenly nodes were getting forked off.

Pure nonsense. The only time core nodes intentionally banned another node was the btc1 nodes which had nothing to do with UASF.

yep fork before activation where more then 50% are thrown off network is never a good way to fake something into activation.
yes it caused some pools and nodes to be forked into their own alt before the activation..
but because that fork was not known/accepted by economic nodes(exchanges) some gave in and upgraded back to the segwit endorsed version

That's nonsense.
SegWit didn't activate by nodes it activated by miners when they reached more than 95% signalling and it was all because of the NYA also known as SegWit2x.

the forks alt(bch) was never intended to be a bitcoin option fight for choice of which should be 'bitcoin' it was just a hole to throw opposition into.

I disagree. "Opposition" didn't move to bcash, those who wanted to make some additional money did.

this method should never be repeated again.

UASF has its usefulness but BIP148 is seriously flawed because it doesn't take miners into consideration at all.

[pooya87]

nodes and miners were dropping off the network.

No they weren't.

so a UASF involves treating peers relaying a different version of block as bad peers. thus ban the peer

That's the definition but things didn't even get to that point since their deadline was never reached and not to mention that these nodes were the small minority.

2 versions of blocks. is a hard fork.

First of all 2 competing blocks (or chains) is a chain split and has nothing to do with the fork being soft or hard.
Secondly there were no 2 "versions of blocks" back in 2017 unless you are counting the shitcoin forks such as BCH, BSV, BTG, BTX,... and 50 others as competing chains?

[pooya87]

incase you cant analyse block data. heres the signals in graphic form note the red line at 45% as of 23rd july.. and sudden jump to 100% 2 weeks later..
hmm wonder how that happened... oh wait. just random coincidence and unrelated to anything(sarc)

That chart is saying exactly what I said.
SegWit activated through SegWit2x (aka NYA) when miners signaled for it using bit 4 an when the numbers reached more than 95% they also set their bit 1 (through BIP141 or SegWit) and signaled for both. Meanwhile UASF support remains close to 10%.

And you haven't been able to show us a single block that was rejected for not signalling SegWit before it was locked in to prove your claims. You keep playing with words.

[NotATether]

oh and um just some info..
if the bitcoin DNS seed servers are bias towards only wanting to table nodes of a certain persuasion(lukes dns seed) they dont need users to download a new version. the dns seed would just stop listing nodes it didnt like so users dont connect to them. (they exist but dont get peers. thus off the network)

What's stopping people (like me) from making a PR to introduce their node with a domain as another DNS seed? One that has a very long uptime of course and is operated by someone who isn't rouge.

[DooMAD]

It was enforced by a User Activated Soft Fork, UASF i.e. forced by a majority of user wallets that adopted the soft fork, miners followed this majurity.

That's not how I recall history unfolding, unless your use of the word "enforced" was simply chosen in error.  "Pressured", perhaps, but "enforced", no.  The threat of a UASF was looming, but miners chose to "lock in" BIP 91 in July 2017.  

its also even now possible to see the acceptance flag was only ~45% right up to end of july

Uh-oh, even though they've had nearly four years to wrap their addled brain around the concept, some people are still unable to discern the difference between "bit 1" (signalling for BIP 141) and "bit 4" (signalling for BIP 91).  You can obsess over the percentage of bit 1 signalling for the rest of forever (and being the utter sadcase you are, I'm sure you will), but that's not the salient percentage in this conversation.

so in your viewpoint of history it just so happen that before the actual activation. nodes and miners were dropping off the network.. but to you that was just coincidence and not linked..

You're still conflating two separate issues.  What you're talking about began on 3rd August 2017.  AFTER BIP 91 LOCKED IN.  I don't know if your issue is literacy or just basic comprehension, but this has been explained to you before.  Several times.  Please take your Trump-esque "alternative facts" elsewhere, you dumpster-fire of a personality.

[DooMAD]

maybe one day you will learn HOW 45% miner flags turned into 100% in a fortnight.

I already know.  I watched it happen in real time.  Right in front of my eyes.  We're all hoping that one day you learn, though.  Once the 80% lock-in threshold was achieved, the writing was on the wall and there wasn't much point resisting it anymore.  I know you're desperate for it to be a conspiracy and you're going to insist for the rest of forever that it was a conspiracy.  But it wasn't.  Even if nodes and miners were disappearing (and I'm still not convinced they were in the kinds of volume you're attempting to convince us they were), you still wouldn't be able to prove that they hadn't left voluntarily to join the BCH fork on 1st Aug 2017.  After all, why would anyone stick around on a network where they disagree with the ideology when they could just build upon that other blockchain instead?  (obviously you can't answer that one, because sadly you're still here on this chain for reasons I can't fathom)

Consider some actual evidence.  If you'd care to look up the historic BTC hashrate for May, June and July 2017, you'll see that the hashrate continued to climb throughout those three months.  No sudden large drops during July when BIP 91 locked in, so miners clearly weren't being forced off in droves as you so ridiculously claim.  It was only once the BCH fork launched on 1st August 2017 that there was a noticeable plummet in the hashrate.  Please present evidence to the contrary, assuming you have any.  Prove that miners were being forced off.  You can't.

the blockchain data does not lie.  [but franky1 does]

Your interpretation of the data leaves much to be desired.  If it's so blatantly obvious that we're lying, please explain how it is that you're the only person who has arrived at this conclusion?  Where are all the people who believe your fantastical version of events?

//EDIT:  I'm weary of rehashing this over and over.  I'll continue any discussions about consensus in general, but I'm not wasting further time and effort on explaining SegWit activation.  It's history now and it's not going to change.

//DOUBLE-EDIT:

the lesson to learn is.. NO NETWORK SPLIT should happen before activation. and only a network split at activation IF full uncoerced/unsplit network gave the network a high majority flag
where by only a small majority split after the activation

a) It certainly didn't occur before lock-in.
b) I'm still not convinced it happened at all.
c) Even if it did happen, Okay, Mr Almighty God-lord, ruler-of-all, whatever you say goes.  We'll just completely forget that freedom is a thing we're allowed to have.  

[nullius]

There is hereby a failure of human language usage:  The word “consensus” is overloaded.

In Bitcoin, the word “consensus” has the very specific technical meaning.  It does not refer to an agreement amongst humans, as in colloquial usage.  Rather, it denotes the resolution of a synchronized state in a distributed system.

Compare and contrast other distributed consensus protocols such as Paxos (the Lamport consensus protocol, not the blockchain company).

In Bitcoin, the consensus means that all nodes arrive at the exact same conclusions about the current global state of the blockchain ledger:  The set of valid transactions that exist, the meaning of each of those transactions, and the order of those transactions.  It means that if Alice sends two transactions that attempt to spend the same coin, then every (honest) node in the world automagically agrees on the decision of which of the two transactions is valid, and which is invalid as a double-spend.  It means that if Mallory mines a block that violates consensus rules, all (honest) nodes file the block in /dev/null as if it never existed—regardless of the POW shown in its block header.  Etc...

The Bitcoin ledger is a single global truth.  Mutually untrusting nodes agree on this one truth, with no central authority to call the shots or enforce rules.  The only information available to each node is a bunch of blobs of data that the node receives from anonymous, potentially hostile parties.  And—the whole thing works!  It is so secure that the network can be trusted with a trillions of dollars worth of total value.

That is the meaning of the Nakamoto Consensus.

[DooMAD]

it was not unified agreement

Apologies, Lord Francis, we weren't aware you had decreed it had to be thus.   

I'm guessing if you had gotten the outcome you wanted, you wouldn't give the slightest toss who disagreed.  Worthless hypocrite.  You're clearly incapable of respecting consensus, yet you have the audacity to wade defiantly into this topic expecting people to care what your opinions are?  I suppose the balls must compensate for the total lack of brains.