Imagine a bitcoin network of 1 computer. (The fake blockchain attack) - page 2.

yogi

legendary

Activity: 947

Merit: 1042

Hamster ate my bitcoin

Quote from: pontiacg5 on November 27, 2013, 12:22:05 PM

If I'm not mistaken the client naturally goes with the chain with the longest proof of work. Seeing as how a single computer chain probably isn't running the same difficulty (or anywhere remotely near it) as the legit chain it should be ignored pretty easily.

The client goes with the chain that took the most computational effort to create, not the longest.

Skybuck

full member

Activity: 385

Merit: 110

Quote from: pontiacg5 on November 27, 2013, 12:22:05 PM

If I'm not mistaken the client naturally goes with the chain with the longest proof of work. Seeing as how a single computer chain probably isn't running the same difficulty (or anywhere remotely near it) as the legit chain it should be ignored pretty easily.

Which cpp file(s) is/are responsible for this ? Perhaps this one:

https://github.com/bitcoin/bitcoin/blob/master/src/main.cpp

Examining it now.

SetBestChain looks promising.

Anyway so far as far as I know bitcoin selects the chain with the most blocks ? and not the chain with the thoughest difficulty ? Is what you are suggesting "thoughest difficulty" ? If so I want to see some prove of that in the source code.

Skybuck

full member

Activity: 385

Merit: 110

Quote from: FenixRD on November 27, 2013, 12:19:18 PM

Quote from: Skybuck on November 27, 2013, 12:02:48 PM

Hello,

Imagine a bitcoin network of 1 computer for the past years of bitcoin's existence.

Theoretically and practically this 1 computer could calculate a blockchain that was just as long if not even 1 block longer than bitcoin's current blockchain. (By a group of computers recalculating this fake block chain incredibly fast in just a few days or so, perhaps even mere hours or minutes Wink

).

Thus a "fake blockchain" could be constructed re-writing the history of bitcoin.

Currently bitcoin is protected with "checkpoints" against such an "easy" re-write of history.

What securities are in place in bitcoin to protect:

1. Current running nodes ?
2. New nodes ?

New nodes seem to be protected against downloading fake block chains by "checkpoints" hardcoded into the bitcoin source code.

Which other security mechanisms exist in bitcoin to protect against such fake block chains ?

Bye,
Skybuck.

Running the QT client each block is a "checkpoint". There are no centralized checkpoints implemented in Bitcoin, though third-party clients sometimes make use of some form of it. You'll certainly have no one who can send or accept payments from you. And presumably you must have tweaked the client to keep it in this state, so really all you have done is created a fork at the point in time that transactions deviated from the majority network. So you have your own coin, let's call it FauxCoin, which nobody but you uses. Feel free to visit the Alt-coin board to attempt to change this.

You are a fool.

https://github.com/bitcoin/bitcoin/blob/master/src/checkpoints.cpp

Perhaps all bitcoin users are fools.

pontiacg5

sr. member

Activity: 364

Merit: 250

If I'm not mistaken the client naturally goes with the chain with the longest proof of work. Seeing as how a single computer chain probably isn't running the same difficulty (or anywhere remotely near it) as the legit chain it should be ignored pretty easily.

FenixRD

sr. member

Activity: 364

Merit: 250

I am Citizenfive.

Quote from: Skybuck on November 27, 2013, 12:02:48 PM

Hello,

Imagine a bitcoin network of 1 computer for the past years of bitcoin's existence.

Theoretically and practically this 1 computer could calculate a blockchain that was just as long if not even 1 block longer than bitcoin's current blockchain. (By a group of computers recalculating this fake block chain incredibly fast in just a few days or so, perhaps even mere hours or minutes Wink

).

Thus a "fake blockchain" could be constructed re-writing the history of bitcoin.

Currently bitcoin is protected with "checkpoints" against such an "easy" re-write of history.

What securities are in place in bitcoin to protect:

1. Current running nodes ?
2. New nodes ?

New nodes seem to be protected against downloading fake block chains by "checkpoints" hardcoded into the bitcoin source code.

Which other security mechanisms exist in bitcoin to protect against such fake block chains ?

Bye,
Skybuck.

Running the QT client each block is a "checkpoint". There are no centralized checkpoints implemented in Bitcoin, though third-party clients sometimes make use of some form of it. You'll certainly have no one who can send or accept payments from you. And presumably you must have tweaked the client to keep it in this state, so really all you have done is created a fork at the point in time that transactions deviated from the majority network. So you have your own coin, let's call it FauxCoin, which nobody but you uses. Feel free to visit the Alt-coin board to attempt to change this.

Skybuck

full member

Activity: 385

Merit: 110

Hello,

Imagine a bitcoin network of 1 computer for the past years of bitcoin's existence.

Theoretically and practically this 1 computer could calculate a blockchain that was just as long if not even 1 block longer than bitcoin's current blockchain. (By a group of computers recalculating this fake block chain incredibly fast in just a few days or so, perhaps even mere hours or minutes Wink

).

Thus a "fake blockchain" could be constructed re-writing the history of bitcoin.

Currently bitcoin is protected with "checkpoints" against such an "easy" re-write of history.

What securities are in place in bitcoin to protect:

1. Current running nodes ?
2. New nodes ?

New nodes seem to be protected against downloading fake block chains by "checkpoints" hardcoded into the bitcoin source code.

Which other security mechanisms exist in bitcoin to protect against such fake block chains ?

Bye,
Skybuck.

Topic: Imagine a bitcoin network of 1 computer. (The fake blockchain attack) - page 2. (Read 1879 times)