2013-11-04 - HackingDistributed.com - Bitcoin Is Broken

[01BTC10]

Bitcoin is broken. And not just superficially so, but fundamentally, at the core protocol level. We're not talking about a simple buffer overflow here, or even a badly designed API that can be easily patched; instead, the problem is intrinsic to the entire way Bitcoin works. All other cryptocurrencies and schemes based on the same Bitcoin idea, including Litecoin, Namecoin, and any of the other few dozen Bitcoin-inspired currencies, are broken as well.

The rest of the article: http://hackingdistributed.com/2013/11/04/bitcoin-is-broken/

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[goxed]

Getting pretty aggressive for attention with Donald duck cartoons no less.

[grondilu]

For some reason the PDF on ArXiv can't be read.

Here is an attempt to compile the source on writelatex.com:

https://www.writelatex.com/478960jtrzzx

[01BTC10]

For some reason the PDF on ArXiv can't be read.

Here is an attempt to compile the source on writelatex.com:

https://www.writelatex.com/478960jtrzzx

Had the same problem but found the PDF somewhere else and I'm hosting it there: https://docs.google.com/file/d/0B0iH5utIT4tkdzU5eFNBRWl5WHc/edit?usp=sharing

Edit: Your PDF looks complete.

[exstasie]

For some reason the PDF on ArXiv can't be read.

Here is an attempt to compile the source on writelatex.com:

https://www.writelatex.com/478960jtrzzx

It's a virus that will steal all of your bitcoins....be careful! haha.

[grondilu]

Haven't read everything yet, but here's a remark already:

« We assume that miners are rational; that is, they try to maximize their revenue, and may deviate from the protocol to do so. »

If they want to maximize their revenue, they may prefer not to attack the system, since it may compromise the whole bitcoin system, and thus the value of bitcoins.   I'm not sure the author took this into account.

PS.

« Selfish miners achieve this goal by selectively revealing their mined blocks to
invalidate the honest miners’ work. Approximately speaking, the selfish mining
pool keeps its mined blocks private, secretly bifurcating the blockchain and cre-
ating a private branch. Meanwhile, the honest miners continue mining on the
shorter, public branch. Because the selfish miners command a relatively small
portion of the total mining power, their private branch will not remain ahead of
the public branch indefinitely. Consequently, selfish mining judiciously reveals
blocks from the private branch to the public, such that the honest miners will
switch to the recently revealed blocks, abandoning the shorter public branch.
This renders their previous effort spent on the shorter public branch wasted,
and enables the selfish pool to collect higher revenues by incorporating a higher
fraction of its blocks into the blockchain. »

So that's basically offline mining.   Hasn't this been discussed many times already?  Anyway I don't see why an offline chain would be longer than the online chain, unless the offline miners have more processing power.  The author seems to do very complicated maths to explain this.  Haven't read it yet.

[Stephen Gornick]

The rest of the article: http://hackingdistributed.com/2013/11/04/bitcoin-is-broken/

Further discussion:

Majority is not Enough: Bitcoin Mining is Vulnerable
 - http://bitcointalk.org/index.php?topic=324413.0

[Bitcoin-development] Auto-generated miner backbone
 - http://sourceforge.net/mailarchive/message.php?msg_id=31597291

The Twitter accounts for the two researchers:
 - http://twitter.com/ittayeyal
 - http://twitter.com/el33th4xor

[grondilu]

Glad to see the dev team is on this.   That's definitely the kind of stuff the bitcoin foundation is useful for.

[kjlimo]

Glad to see the dev team is on this.   That's definitely the kind of stuff the bitcoin foundation is useful for.

Is on it as in giving articles/opinions on these topics?  Or trying to fix a problem?

I assume there's no problem.  Granted, it's still an experiment, but if it could be broken, wouldn't it have been done already?

[balanghai]

Broken a very provocative word. Sure traffic is heading his websites and earning revenue. Also vulnerable is a more appropriate word for this. So if the dev knows this, how will they stop the offline miners?

[LanYu]

In the paper, the author claims that a pool could reveal a chain of prior work to the network.

My question is, wouldn't this introduce a fork into the chain?

[prophetx]

The rest of the article: http://hackingdistributed.com/2013/11/04/bitcoin-is-broken/

Further discussion:

Majority is not Enough: Bitcoin Mining is Vulnerable
 - http://bitcointalk.org/index.php?topic=324413.0

[Bitcoin-development] Auto-generated miner backbone
 - http://sourceforge.net/mailarchive/message.php?msg_id=31597291

The Twitter accounts for the two researchers:
 - http://twitter.com/ittayeyal
 - http://twitter.com/el33th4xor

i don't get it... different versions of this article came out over the last several hours.  articles like this don't get spread at so many known outlets without a coordinated effort and a media embargo...

connect the dots...