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Comment by tdryja | Hacker News Reader

"Bitcoin Unlimited" has no maximum block size, hence the name.

There are many problems which arise from unbounded transaction rates in Bitcoin. The most fundamental is that long term the coinbase reward is zero, and transaction fees are the only reason to create new blocks. Without artificial scarcity of block space (artificial in the sense of beyond what hardware can support) transaction fees would tend to zero, and mining would no longer generate revenue.

LN is proposed to allow many users and many transactions (when nodes cooperate) while keeping the security properties of Bitcoin (when nodes don't).

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Response: https://bitco.in/forum/threads/gold-collapsing-bitcoin-up.16...

> Without artificial scarcity of block space

Or natural scarcity, which already exists.

Mining does not need to be profitable. People always make the mistake in thinking that if mining ceases to be profitable that mining would suddenly stop. That is simply not how it works. It is more economical to buy tomatoes at the grocery store, but that doesn't stop people from growing tomatoes in their backyard.

Mining costs millions of dollars per day in electricity costs. I guess we can just expect a few people to burn a hole in their pocket for the good of the network?

Sorry to be pedantic, but I do believe the daily cost of mining is closer to $250,000 - $750,000. Not a small number, but also not millions per day.

I'm a physicist so naturally I do all back-of-the-envelope calculations to one-significant figure with rounding at each step. :)

My own estimation is between $400k per day (hard lower bound) and $800k per day depending on assumptions about hardware efficiency, although around $100k / day was added in the last week in a trend that is continuing, so $1MM/day will very quickly be accurate.

This reflects a misunderstanding of the drivers of mining costs.

Mining only costs a lot because coin value is high and the block reward is high. This means miners are willing to spend more to win the reward.

As the block reward lowers then mining becomes funded entirely by equilibrium-priced fees.

Oh I understand mining economics quite well. The comment I was responding to however claims that some people will continue to mine at a loss after the subsidy is negligible. However that assumes that people would be willing lose hundreds of millions of dollars per year on power costs just to meet current security levels, let alone whatever level of higher security might be required in a moonshot scenario.

Millions of people collectively losing hundreds of millions of dollars a year is less than $1/month individually.

Welcome to HN

If you knew anything about Bitcoin Unlimited I am sure you would have come across its most fundamental aspect - moving the blocksize limited from the hardcoded centralised protocol layer to the transport or messaging layer thus allowing each node operator to choose the limit in a decentralised fashion so creating an emergent consensus.

In regards to your speculative economics, as I am sure you are aware, storage/bandwith/processing/validation and mining has costs. No one would therefore mine a transaction for free in 20 years because if they do so they would soon go bankrupt.

Bitcoin's design has an inbuilt long term solution. Reward miners early on - grow adoption - increase transactions to a "very large number" - charge pennies out of millions of transactions - profit.

Finally, LN may be secure for microtransactions. It is in no way secure for decent transactions. There are millions of ways it can be hacked even now that it only exists in speculative heads. Once it becomes hardcode implemented I am sure attack vectors will only increase much further.

> If you knew anything about Bitcoin Unlimited I am sure you would have come across its most fundamental aspect - moving the blocksize limited from the hardcoded centralised protocol layer to the transport or messaging layer thus allowing each node operator to choose the limit in a decentralised fashion so creating an emergent consensus.

If you knew anything about Bitcoin, you'd know that this is a sure-fire way to get forked off the network and ripped off by double-spends. The nature of Nakamoto consensus is such that consensus parameters are not up to vote.

> The nature of Nakamoto consensus is such that consensus parameters are not up to vote

"The proof-of-work also solves the problem of determining representation in majority decision making. If the majority were based on one-IP-address-one-vote, it could be subverted by anyone able to allocate many IPs. Proof-of-work is essentially one-CPU-one-vote." - Nakamoto

Not over the consensus parameters. You could have infinite hash power, but if your blocks are invalid they will be ignored.

https://github.com/bitcoin/bitcoin/blob/be9a9a3d2253ceccf123...

Um, I'm not sure why you are pointing to that? ISM is used for soft-fork upgrades, which do not revert existing consensus rules. You can have a ISM vote over a new block size, but old clients will still reject the bigger blocks.

The upgrades are triggered by a super-majority of blocks of a certain version. This version maps to a possible new consensus rule. Block creation is a product of computational work. Therefore there is a precedent for CPUs/ASICs voting on the consensus rules of the system.

> ISM is used for soft-fork upgrades, which do not change existing consensus rules.

"Soft-forks" do change existing consensus rules. Will a miner's v1 blocks be accepted by the majority of the network today?

Which has no relevance to this conversation about BU and block size. Block size is not a parameter you can force on upgraded nodes by soft-fork.

You made the claim that under "Nakamoto consensus" the consensus parameters are not up for a vote. A correction seemed warranted.

> Block size is not a parameter you can force on upgraded nodes by soft-fork.

Isn't this what the Segregated Witness proposal[1] effectively does? The new limit proposed would be 4MB with an expected confirmed transaction throughput increase on the order of 2x.

To quote Pieter:

"Another way of looking at it, is that we raise the block size to 4 MB for the witness part, but the non-witness has same size."

[1] http://diyhpl.us/wiki/transcripts/scalingbitcoin/hong-kong/s...

"If"

And if they are not?

> "Proof-of-work is essentially one-CPU-one-vote." - Nakamoto

Yes this is one of the things that Satoshi got wrong. "1 CPU = 1 vote" is wrong. Turns out that Proof-of-Work is unrelated to the physical quantity of CPUs, rather it's more about computation and hashrate. Also it's a stretch to call Proof-of-Work a vote ..... it's not an election, it's more like a random lottery or something.

He stated PoW was _essentially_ one-CPU-one-vote. It's clear that the intent is to mean hashrate, or CPU power as he phrases it multiple times in the same paper.

> it's not an election, it's more like a random lottery or something.

A random lottery where your odds of winning directly correlate with your CPU power / hashrate. The more you win the more influence you have over the state of the network. Comparing it to a vote is a reasonable analogy.

> The nature of Nakamoto consensus is such that consensus parameters are not up to vote.

One of two things must therefore be true:

1. If consensus parameters cannot be voted on then Bitcoin is a failure, and Core's huge war against upstarts like XT and BU are totally misplaced (since as you say they cannot be changed by vote) or

2. You're dead wrong

If consensus parameters are not up to vote then obviously XT simply cannot be "voted in", so why fight it?

If consensus parameters are not up for a vote then Bitcoin loses permissionlessness and censorship resistance: a hostile actor merely needs to infiltrate the governance structure of one ragtag dev team and he can block certain transactions or indeed greatly harm the network by inserting consensus code to keep undesirable txns out or by making the rules unworkable. Since nobody can vote the bad rules out, the network just has to accept the bad rules and implode.

If consensus rules cannot be voted on then permissionless innovation of the system is thwarted or impossible. If I have a great idea for a consensus rule innovation, I have to get permission from the keepers of the consensus rules to add my rule change.

If consensus rules are not up for vote then if a supermajority of users including miners attempt to change the rules by running different rules, nothing will happen, because the rules "weren't up to vote." But it is objectively the case that if this were to happen, then the rules would be changed because a majority of voters agreed with the change. This is the defacto behavior of Bitcoin.

Methinks that #2 is the case. Consensus rules, as a simple matter of fact, are amenable to change by a simple supermajority of CPU votes from a majority of miners and nodes.

You are free to read the code and see for yourself.

It is my reading of the code and understanding of the emergent crypto-economy that leads me to these self-evident conclusions.

Are you refuting my points or agreeing with them? If you have an actual rebuttal to any of them, I'm interested in hearing it.

> 1. If consensus parameters cannot be voted on then Bitcoin is a failure, and Core's huge war against upstarts like XT and BU are totally misplaced (since as you say they cannot be changed by vote)

Eagerly awaiting a substantive response to this by maaku.

However I disagree with the BU proposition that unrestrained "voting" on max blocksize is a good idea. It doesn't stand up to attacks by a small amount of hash power.

> > 1. If consensus parameters cannot be voted on then Bitcoin is a failure

> Eagerly awaiting a substantive response to this by maaku.

I am very much not maaku, but first it's obvious that Proof-of-Work has not been used to decide consensus protocol parameters (it's used for transaction ordering and establishing the consensus history). Second, Bitcoin success or failure is entirely unrelated to how the protocol wasn't designed to vote on consensus protocol parameters.

> it's obvious that Proof-of-Work has not been used to decide consensus protocol parameters

Every "soft-fork" to date has used PoW to activate new consensus rules by requiring block version super-majority.

> Every "soft-fork" to date has used PoW to activate new consensus rules

Consensus rule parameters are things like "max block size". However, there have been some proposals for extension blocks to increase block size without requiring a hard-fork (e.g. using a soft-fork mechanism).

Of course proof of work has always been used to decide consensus parameters. It's just tuat no controversial changes / failures to change have ever been put to the vote.

As long as the changes are non controversial then miners and nodes simply act at a rubber stamp. But it's unrealistic to think no important issues will be controversial.

If consensus changes arent up for CPU vote, then you tell me what happens if a supermajority of miners and nodes decide to run software with different consensus rule from Core? Sounds like a CPU vote too me.

double-spend is now a feature, it's called rbf.

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