Bitcoin Killswitch

[RyNinDaCleM]

you should have been there

poeple were still making TX as the chine was forking and every single TX got through onto the right chain

I was impressed.

And assuming i (or $whoever) had a/several blockchains dozens of blocks longer than the "valid" blockchain? What then?

Yes, the longer chain is technically recognized as the "correct" chain by the network, but this has been rolled back with a fork before, and as Adam said, an upgrade to the client would be necessary by the majority (>50%) of the network.

This is the same thing as 51% attacks

[adamstgBit]

you should have been there

poeple were still making TX as the chine was forking and every single TX got through onto the right chain

I was impressed.

And assuming i (or $whoever) had a/several blockchains dozens of blocks longer than the "valid" blockchain? What then?

Yes, the longer chain is technically recognized as the "correct" chain by the network, but this has been rolled back with a fork before, and as Adam said, an upgrade to the client would be necessary by the majority (>50%) of the network.

add to that, that the majority overrule hashing power.

if marjory says "block that mega miner with 30% mining power because we don't like him"

hes blocked.

of course its very hard to get >51% to all agree on something. but in this most ridiculous sanrio it would fly.

[Elwar]

Hmm, so we have this ledger with every Bitcoin transaction going back to the beginning. Every 10 minutes a new block is added to show the latest transactions.

Then some "kill switch" does what exactly? Wipes out the ledger? On everyone's computer? Even those that are turned off? Even those not connected to the Internet?

It would be harder to do than wipe out all bank accounts of all banks, all stocks, bonds, etc in the whole world.

[An amorous cow-herder]

Yes, the longer chain is technically recognized as the "correct" chain by the network, but this has been rolled back with a fork before, and as Adam said, an upgrade to the client would be necessary by the majority (>50%) of the network.

This is the same thing as 51% attacks

No, it is not.
In the real world the the block chain does not have a constant exponential factor. Any deviation results in a suboptimal difficulty for the real chain compared to a "perfect" chain with a constant exponential factor.
Thus an attacker would save time or difficulty by choosing a constant exponential factor for difficulty increasements.

[An amorous cow-herder]

Hmm, so we have this ledger with every Bitcoin transaction going back to the beginning. Every 10 minutes a new block is added to show the latest transactions.

Then some "kill switch" does what exactly? Wipes out the ledger? On everyone's computer? Even those that are turned off? Even those not connected to the Internet?

It would be harder to do than wipe out all bank accounts of all banks, all stocks, bonds, etc in the whole world.

No, the only safety are the so called checkpoints. Those are hardcoded into the clients. In other words all transactions since the last hardcoded checkoint would be save.
But otherwise, yes, it doesnt matter if the PCs are turned on or off.

[Elwar]

Would we have to forget some of those transactions? Like how some of the initial transactions done by Satoshi are so famous?

Memory wipe as well?

[RyNinDaCleM]

Hmm, so we have this ledger with every Bitcoin transaction going back to the beginning. Every 10 minutes a new block is added to show the latest transactions.

Then some "kill switch" does what exactly? Wipes out the ledger? On everyone's computer? Even those that are turned off? Even those not connected to the Internet?

It would be harder to do than wipe out all bank accounts of all banks, all stocks, bonds, etc in the whole world.

It would be difficult, yes! But not impossible.
It wouldn't matter about the disconnected clients. Once they sync to the network, if for instance something was added to that final block to make the client no longer start or recognize the chainstate, then every client would be broken.

Yes, the longer chain is technically recognized as the "correct" chain by the network, but this has been rolled back with a fork before, and as Adam said, an upgrade to the client would be necessary by the majority (>50%) of the network.

This is the same thing as 51% attacks

No, it is not.
In the real world the the block chain does not have a constant exponential factor. Any deviation results in a suboptimal difficulty for the real chain compared to a "perfect" chain with a constant exponential factor.
Thus an attacker would save time or difficulty by choosing a constant exponential factor for difficulty increasements.

The 51% comment was more gear toward the majority of the network would have to agree on one chain. Not that this hypothetical "bug" would be synonymous to a 51% attack

[An amorous cow-herder]

The 51% comment was more gear toward the majority of the network would have to agree on one chain. Not that this hypothetical "bug" would be synonymous to a 51% attack

Without checkpoints a competing blockchain starting of the genesis block with a simple 7% difficulty growth per switch would be at the same length as the current blockchain. And just be running at ~ 300GH/s.
Obviously its a lot harder thanks to checkpoints.
But this means the trust in the algorythm has been breached and instead the trust of "core developers" is required to include checkpoints.
This shouldnt be necesarry. The difficulty algorhythm is imho flawed. The simple average of the last 2016 blocks is just plain stupid.

[adamstgBit]

the majority overrule hashing power.

you know what i mean?
i'm wondering if you guys agree with this or not?

[An amorous cow-herder]

the majority overrule hashing power.

you know what i mean?
i'm wondering if you guys agree with this or not?

Whatever you seem to mean is not true. The hardcoded checkpoints decided by devs overrule overything.

[DeathAndTaxes]

Without checkpoints a competing blockchain starting of the genesis block with a simple 7% difficulty growth per switch would be at the same length as the current blockchain. And just be running at ~ 300GH/s.

It would help if you learned how Bitcoin works.   "Longest chain" doesn't mean highest block height it means the chain consisting of valid blocks with the highest total cummulative difficulty.   Your chain with 7% difficulty growth every 2016 blocks would never be the longest chain.  There are no shortcuts to the longest chain.    The current longest chain is ~2^70 hashes worth of work.  The only way to make one longer would be to do more work.

But this means the trust in the algorythm has been breached and instead the trust of "core developers" is required to include checkpoints.

The checkpoints are not necessary to prevent an attack.  An attacker however could waste a lot of time and resources of new bootstrapping nodes by feeding them giant worthless low difficulty chains. Any well connected node can identify the correct longest chain but time/resources spent validating a chain to find out it is inferior is still wasted time/resources. Checkpoints reduce the amount of resources an attacker could could cause a new node to waste.

The newest checkpoint is more than 7 months old.  That alone should help your realize it isn't a security mechanism.  I mean does anyone think limiting an attacker to "only" rolling back 7 months of the blockchain would be an effective defense?  Everyone is going to say "good thing for that checkpoint it limited us to only 7 months of double spends, had it been 8 months that might have shaken my confidence"?

[vuduchyld]

Well, I always assumed "Speculation" meant speculating about price.  But I guess there are other kinds of speculation I had not co sidered. Well played!

[TwinWinNerD]

Basicly its a fairly hyptothetical question.

But lets, just for a moment assume bitcoin had something like a "kill-switch".
A method that, by design, would revert all transactions that have ever been done.

What would be the consequences?

Someone would fix it and relaunch it starting from the last "old" block. This would happen within hours after the incident.

This has actually happend once, where 184,000,000 bitcoins were created due to a floating integer bug.

[adamstgBit]

the majority overrule hashing power.

you know what i mean?
i'm wondering if you guys agree with this or not?

Whatever you seem to mean is not true. The hardcoded checkpoints decided by devs overrule overything.

say everyone wants to kick off a huge malicious miner off the network, ( it makes no sense for a miner to act maliciously but lets say it happening ), someone with like 30% hashing power start attacking, everyone wants to kick him off, the core is patched to block this miner, everyone upgrades because they wish it, and there you go, majority overruled hashing power.

point is hashing is just a way of achieving consensus in an automated way, and can be side swiped given "manual" consensus.

[Raystonn]

the majority overrule hashing power.

you know what i mean?
i'm wondering if you guys agree with this or not?

Whatever you seem to mean is not true. The hardcoded checkpoints decided by devs overrule overything.

say everyone wants to kick off a huge malicious miner off the network, ( it makes no sense for a miner to act maliciously but lets say it happening ), someone with like 30% hashing power start attacking, everyone wants to kick him off, the core is patched to block this miner, everyone upgrades because they wish it, and there you go, majority overruled hashing power.

point is hashing is just a way of achieving consensus in an automated way, and can be side swiped given "manual" consensus.

The majority of the hashing power must agree to this change.  So it's not that the "majority overruled hashing power".  It's just that the majority of the hashing power overruled the minority, as in any other double-spend attempt.

[TwinWinNerD]

the majority overrule hashing power.

you know what i mean?
i'm wondering if you guys agree with this or not?

Whatever you seem to mean is not true. The hardcoded checkpoints decided by devs overrule overything.

say everyone wants to kick off a huge malicious miner off the network, ( it makes no sense for a miner to act maliciously but lets say it happening ), someone with like 30% hashing power start attacking, everyone wants to kick him off, the core is patched to block this miner, everyone upgrades because they wish it, and there you go, majority overruled hashing power.

point is hashing is just a way of achieving consensus in an automated way, and can be side swiped given "manual" consensus.

There is literally no way this would work. You could block IPs submitting blocks, or find another workaround.
BUT if this guy is really malicious, than he is watching everything very carefully and will be proactively changing his IP and setting to something different.

Also, there are "Red Alert" scenarios, that would fix malicious attacks in the shortterm, even 51% attacks, but there is nothing longterm!

[ForgottenPassword]

The easiest way to do this is by destroying every copy of the Blockchain in existance and inducing amnesia in every Bitcoin user.

Anything less than that will be rolled back. You can have a kill switch that works "temporarily" and may cause mass panic and losses for Bitcoin users, but whatever you do can be undone.

[adamstgBit]

the majority overrule hashing power.

you know what i mean?
i'm wondering if you guys agree with this or not?

Whatever you seem to mean is not true. The hardcoded checkpoints decided by devs overrule overything.

say everyone wants to kick off a huge malicious miner off the network, ( it makes no sense for a miner to act maliciously but lets say it happening ), someone with like 30% hashing power start attacking, everyone wants to kick him off, the core is patched to block this miner, everyone upgrades because they wish it, and there you go, majority overruled hashing power.

point is hashing is just a way of achieving consensus in an automated way, and can be side swiped given "manual" consensus.

There is literally no way this would work. You could block IPs submitting blocks, or find another workaround.
BUT if this guy is really malicious, than he is watching everything very carefully and will be proactively changing his IP and setting to something different.

Also, there are "Red Alert" scenarios, that would fix malicious attacks in the shortterm, even 51% attacks, but there is nothing longterm!

exactly.

all i'm trying to say is that, its our network, and we choose how it works in every detail, just because someone has alot of hashing power doesn't give him any real, long term, power over the system, the will of the majority supersede all. hashing power will ALWAYS service US, the moment it doesn't we ignore it

[TwinWinNerD]

the majority overrule hashing power.

you know what i mean?
i'm wondering if you guys agree with this or not?

Whatever you seem to mean is not true. The hardcoded checkpoints decided by devs overrule overything.

say everyone wants to kick off a huge malicious miner off the network, ( it makes no sense for a miner to act maliciously but lets say it happening ), someone with like 30% hashing power start attacking, everyone wants to kick him off, the core is patched to block this miner, everyone upgrades because they wish it, and there you go, majority overruled hashing power.

point is hashing is just a way of achieving consensus in an automated way, and can be side swiped given "manual" consensus.

There is literally no way this would work. You could block IPs submitting blocks, or find another workaround.
BUT if this guy is really malicious, than he is watching everything very carefully and will be proactively changing his IP and setting to something different.

Also, there are "Red Alert" scenarios, that would fix malicious attacks in the shortterm, even 51% attacks, but there is nothing longterm!

exactly.

all i'm trying to say is that, its our network, and we choose how it works in every detail, just because someone has alot of hashing power doesn't give him any real, long term, power over the system, the will of the majority supersede all.

Bitcoin could as a last resort become a pure POS coin for a while too.

[ForgottenPassword]

Also, there are "Red Alert" scenarios, that would fix malicious attacks in the shortterm, even 51% attacks, but there is nothing longterm!

Sure there is. If we are being 51% attacked by a miner using SHA256 ASICS we could switch to another hashing algorithm. If we are being 51% attacked by some multi-purpose hardware that can efficiently run many hashing algorithms, then we can replace the POW system with something else.

While these kind of changes will be hard to swallow and you may have a hard time convincing people to make these kind of changes, they are always an option.