YEAH! No more taxes! WE NEED TRANSACTION FEES!!!

And how it is better than centralized banks? If your bank or government "turns out to be bad" - you can use other bank.

Myth #12: It is decentralized.

No, it is centralized. And it has central authority which can steal all your BTC - https://bitcointalk.org/index.php?topic=371635

There is some guarantee: https://github.com/bitcoin/bitcoin/blob/285cf7a1a6cb660b57cbc75f63e49736b51d705e/src/main.cpp#L2255-L2260

P.S. Thanks for summarizing paper references!

Unbeatable arguments, thank you.


Do you understand that this option is protocol specification change? It effectively forks blockchain.

Yes, they are centralization. But as long as they do not adjust blockchain on regular basis (select which chain is good and which is not) - they gain trust of users.


Yes, but the problem is that the client with checkpoints and one without - are not 100% compatible with each other. Checkpoints are not just cosmetic change.


Bitcoin already has mechanism to achieve consensus - voting by computing resources, it should not be substituted by any centralized authority.

Of course hidden fork crunched at high speed in shadow is unlikely, and maybe checkpoints do not harm due to low probability of such fork.
But they harm in other way - they compromise Bitcoin decentralization, which is in my opinion is the biggest attractive feature of Bitcoin.
Today they add checkpoints (this effectively changes protocol specification), tomorrow they could freeze BTC on your address, by adding small tweaks to validation routine (just like checkpoints validation).

Yes - I considered this. I think it is not a problem, because it is very unlikely that someone can prepare 0.01*MaxBlocks different blocks (unchained, as you noted) which have accumulated difficulty more than 1% or so of total accumulated work spent on main chain for whole time of Bitcoin existence.

I should look closer to your proposal. For now I have one question:
Does "up" link points to future? If so - is it included in block hash or can it be falsified?

I agree, for now and most likely for future downloading all block headers is not an issue. So don't even need to adjust protocol.

Yes, this is the key for improvement. It does not have to provide strict upper_bound, but something that >= strict_upper_bound.
Plus, if this approach will be accepted, we should add ability to request block headers sorted by difficulty, starting with the most expensive one and continue in descending order. This would allow to detect flood with even less traffic, like few percents of Max_Blocks.

I think this idea should be discussed first in separate topic. Then, as I understand it should go to Bitcoin Improvement Proposals.

Again, it is possible to solve this problem by other approaches.
For example via MAIN_CHAIN_MIN_POW as suggested above - it does not compromises decentralization.

We know when Bitcoin was released, we know current date - we can calculate upper bound for block count in any chain.
When somebody tries to send us old chain - we ask it to sent block headers sorted by difficulty, starting with the most expensive one and continue in descending order. 1% of top block headers should have at least 0.01*MAIN_CHAIN_MIN_POW accumulated difficulty, if it is not - then it is fake, else continue, and so on.

I am not sure if it is correct to compare marketcap vs money supply, because you cannot sell all bitcoins at stock price. Once you will start selling - it will go down fast.

Even if it was done for the purposes of optimization - it is still protocol specification change. Clients with disabled "optimization" could accept some branches which would be rejected by client on default settings.

There are other possible approaches to do such kind of optimization, for example MAIN_CHAIN_MIN_POW described above, but it does not compromises decentralization trust as checkpoints do.

Checkpoints were put by small group of people, most of people even do not heard about checkpoints - and continue to think about Bitcoin as pure decentralized currency, while it is not.


Protocol rules allows to choose other branch if it has more accumulated difficulty, even if it is rooted in old blocks before checkpoints. Checkpoints override those rules - they essentially change protocol specification. By adding new checkpoint - you are forking protocol specification.
Choice of checkpoints should be done decentralized - by voting, and Bitcoin already has voting mechanism - vote by computing work. But if voting happens by hard checkpoints, selected by dozen of people - then it is centralized, with all bad sides of centralization.

I did read this thread, and several old ones: https://bitcointalk.org/index.php?topic=437 , https://bitcointalk.org/index.php?topic=1647
Do you have any particular objection to discuss?

Bitcoin is decentralized. And no small group of people should decide which branch is correct and which is not.
Checkpoints hardcoded in code were selected by small group of people.
But if Bitcoin is still claimed to be decentralized, not controlled by government, small group of people (who can be blackmailed, or forced by thermo-rectal cryptanalysis) - then only majority of users should have right to make decision.

Users should vote on which branch is correct and which is not. Bitcoin already has such voting mechanism - vote by computing power.


Of course hidden fork crunched at high speed in shadow is unlikely, and maybe checkpoints do not harm due to low probability of such fork.
But they harm in other way - they compromise Bitcoin decentralization, which is in my opinion is the biggest attractive feature of Bitcoin.
Today they add checkpoints, tomorrow they could freeze BTC on your address, by adding small tweaks to validation routine (just like checkpoints validation).

Checkpoints add almost no value - they do not prevent offensive usage of high computing power, but they trading off fair amount of credibility.
Nobody except majority should have control over blockchain, and Bitcoin's definition of majority is computing power.
Otherwise users must know that blockchain is controlled by small group of human being.

So, what does it solve?


If somebody has huge computing power - it can ruin bitcoin in many ways. Checkpoints eliminate only one of ways, but it still can be destroy in many other ways with such computation power.
Let say, there 32 ways to destroy Bitcoin using high computing power, checkpoints eliminates only 1 of 32. But there still 31 other ways to use this power - so, really checkpoints do not bring anything except compromised credibility of decentralization.

Thanks for links - it just shows that many peoples have similar view that creditability is compromised by checkpoints, and checkpoints solves really tiny problem, which is not an issue at all.
On the other side developers still did not removed checkpoints since 2010 (congrats, nice decentralization, and consensus!) because they afraid of something, or have some strange interests to destroy Bitcoin credibility.

Bitcoin advertised decentralization as the main feature. I think people should know that it is not as decentralized as advertised.

I agree, we should move to https://bitcointalk.org/index.php?topic=194078.40 (now I can post to it).
If anyone feels that this is important issue - please, post a couple of sentences here - https://bitcointalk.org/index.php?topic=194078.40 , in order to show attention/importance.