Blockchain.info misreports origins (Was:Swiss University jumps into mining game)

[Gyrsur]

I dont know whether they mine with full power yet, but its not 51%, its 8.547% actually.


Number of Blocks relayed by 82.130.102.160: 20
First block relayed at Blockheight: 200691
Current Blockheight: 200925
dBlockheight=200925-200691=234 -> they have competed for 234 blocks yet

20/234*100%= 8.547%

They have currently relayed 8.547% of all blocks they have competed for.

what is the timeframe for an 51% attack. 6 blocks?

[Gyrsur]

... Until now, double-spending attacks on fast pay-
ments in Bitcoin or mechanisms for their prevention
have not been studied. In this work, we analyze
double spending attacks in detail and we demon-
strate that double-spending attacks can be mounted
on currently deployed version of Bitcoin, when used
in fast payments. We further show that the measures
recommended by Bitcoin developers for fast trans-
actions are not always effective in resisting double-
spending; we argue that if those recommendations
are followed, double-spending attacks on Bitcoin
are still possible. Finally, we propose a lightweight
countermeasure to detect double-spending attacks in
fast transactions.

More specifically, our contributions in this paper
can be summarized as follows:

We measure and analyze the time required to con-
firm transactions in Bitcoin. Our analysis shows
that transaction confirmation in Bitcoin can be
modeled with a shifted geometric distribution and
that, although the average time to confirm transac-
tions is almost 10 minutes, its standard deviation is
approximately 15 minutes. We argue that this hin-
ders the reliance of transaction confirmation when
dealing with fast payment scenarios.

We thoroughly analyze the conditions for perform-
ing successful double-spending attacks against fast
payments in Bitcoin. We then present the first
comprehensive double-spending measurements in
Bitcoin. Our experiments were conducted us-
ing modified Bitcoin clients running on a hand-
ful of hosts located around the globe. Our results
demonstrate the feasibility and easy realization of
double-spending attacks in current Bitcoin client
implementations.

We explore and evaluate empirically a number of
solutions for preventing double-spending attacks
against fast payments in Bitcoin. We show that the
recommendations of Bitcoin developers on how to
counter double-spending are not always effective.
Leveraging on our results, we propose a lightweight
countermeasure that enables the secure verification
of fast payments. ...

source?

EDIT: https://bitcointalk.org/index.php?topic=113654.msg1228213#msg1228213

[elux]

Swiss... they have something to defend

Yes. Bitcoin is the new Swiss Bank Account.  

This is not a bad thing. That is a legitimate organization, they are not doing it with hostile intent. Very interesting though!

Of course ETH Zürich is legitimate. However, they could still be Bitcoin hostile.  

It's a relief to see that this is a research operation. I'd be rather more concerned if this was an unidentified organization with unknown intent.

I was quite astounded to discover that their group (or indeed any organization) was able to roll out enough mining power to find 7 blocks in 70 minutes.

Pretty impressive, if it's just for a feasibility experiment.

[Spekulatius]

I dont know whether they mine with full power yet, but its not 51%, its 8.547% actually.


Number of Blocks relayed by 82.130.102.160: 20
First block relayed at Blockheight: 200691
Current Blockheight: 200925
dBlockheight=200925-200691=234 -> they have competed for 234 blocks yet

20/234*100%= 8.547%

They have currently relayed 8.547% of all blocks they have competed for.

what is the timeframe for an 51% attack. 6 blocks?

+1

[elux]

I dont know whether they mine with full power yet, but its not 51%, its 8.547% actually.


Number of Blocks relayed by 82.130.102.160: 20
First block relayed at Blockheight: 200691
Current Blockheight: 200925
dBlockheight=200925-200691=234 -> they have competed for 234 blocks yet

20/234*100%= 8.547%

They have currently relayed 8.547% of all blocks they have competed for.

what is the timeframe for an 51% attack. 6 blocks?

IIRC, maintaining a supermajority attack gets exponentially hard over n-blocks.

Hence: "Double-Spending Attacks on Fast Payments in Bitcoin"

[Gyrsur]

Paper will appear:

http://www.syssec.ethz.ch/research/publications

EDIT: "Two Bitcoins at the Price of One? Double-Spending Attacks on Fast Payments in Bitcoin" I'm looking forward to double my bitcoins! 

[Spekulatius]

I dont know whether they mine with full power yet, but its not 51%, its 8.547% actually.


Number of Blocks relayed by 82.130.102.160: 20
First block relayed at Blockheight: 200691
Current Blockheight: 200925
dBlockheight=200925-200691=234 -> they have competed for 234 blocks yet

20/234*100%= 8.547%

They have currently relayed 8.547% of all blocks they have competed for.

what is the timeframe for an 51% attack. 6 blocks?

IIRC, maintaining a supermajority attack gets exponentially hard over n-blocks.

Hence: "Double-Spending Attacks on Fast Payments in Bitcoin"

Unless you have 51% of the whole network's hashing power right?

[yochdog]

Jeesus......that is a lot of power to just "flip the switch" on.

I would love to know what they are running. 

[elux]

Unless you have 51% of the whole network's hashing power right?

No, it's still exponentially difficult over larger numbers of blocks. (Page 8 in the Satoshi whitepaper)

Edit: I may have been wrong about this.

The Bitcoin whitepaper doesn't discuss cases where the attacker's mining power is above 0.3

By Satoshi's analysis, doesn't it get exponentially hard for honest miners to catch up to an attacker, if the attacker controls >50% of mining power, not just blocks solved?

Haven't thought much about majority attack feasibility before today.


Thankfully: "[2] In our experiments, we solely used Bitcoin wallets and
accounts that we own; other Bitcoin users were not affected by our experiments."

These guys didn't steal anyone else's money. But there is a flip side to that coin.

[Isokivi]

Jeesus......that is a lot of power to just "flip the switch" on.

I would love to know what they are running. 

+1

Anyone working on this experiment care to elaborate, Im sure one or more of you are on this forum.

[Aseras]

Jeesus......that is a lot of power to just "flip the switch" on.

I would love to know what they are running. 

gpumax to a solo custom miner?

[cedivad]

Maybe they have tons of fpga unused? They talked about cheap double spending. I don't know how they accounted for 10% of the network power in a "cheap" way.

Maybe they have access to supercomputers we can only dream off.

They are 500Km away, I should go there and investigate

[yochdog]

Purchases do not appear to be running at GPUmax.......

[Spekulatius]

Maybe they have tons of fpga unused? They talked about cheap double spending. I don't know how they accounted for 10% of the network power in a "cheap" way.

Maybe they have access to supercomputers we can only dream off.

They are 500Km away, I should go there and investigate

give em a call, fake a Swiss accent and they won't even know you are from the internet

[cedivad]

They speak Italian, French and German in Swiss, depending on the region. I think that I should sleek in English, lol.

Why don't we simply email them? Their website => lab email, done.

""How the hell are you mining so fast?"""

[Gyrsur]

Maybe they have tons of fpga unused? They talked about cheap double spending. I don't know how they accounted for 10% of the network power in a "cheap" way.

Maybe they have access to supercomputers we can only dream off.

They are 500Km away, I should go there and investigate

give em a call, fake a Swiss accent and they won't even know you are from the internet

did you ever tried to fake a swiss accent? very impossible! they have different accent in every canton and every village. bad idea!  

[greyhawk]

, fake a Swiss accent

Hahahahahahahahahaha! 

[Spekulatius]

Maybe they have tons of fpga unused? They talked about cheap double spending. I don't know how they accounted for 10% of the network power in a "cheap" way.

Maybe they have access to supercomputers we can only dream off.

They are 500Km away, I should go there and investigate

give em a call, fake a Swiss accent and they won't even know you are from the internet

did you ever tried to fake a swiss accent? very impossible! they have different accent in every canton and every village. bad idea!  

In that case just choke up as many croutons from the back of your throat as possible and say you come from the most backward village of them all!

[server]

Maybe they have tons of fpga unused? They talked about cheap double spending. I don't know how they accounted for 10% of the network power in a "cheap" way.

Maybe they have access to supercomputers we can only dream off.

They are 500Km away, I should go there and investigate

give em a call, fake a Swiss accent and they won't even know you are from the internet

did you ever tried to fake a swiss accent? very impossible! they have different accent in every canton and every village. bad idea!  

ok, lol but this is Zurich, north of Swiss, so they speak german...

[Gyrsur]

Maybe they have tons of fpga unused? They talked about cheap double spending. I don't know how they accounted for 10% of the network power in a "cheap" way.

Maybe they have access to supercomputers we can only dream off.

They are 500Km away, I should go there and investigate

give em a call, fake a Swiss accent and they won't even know you are from the internet

did you ever tried to fake a swiss accent? very impossible! they have different accent in every canton and every village. bad idea!  

In that case just choke up as many croutons from the back of your throat as possible and say you come from the most backward village of them all!

bad idea too! I dont want to get a bullet in my head!   they get their army gun to home if they leave the regular army service but without cartridges. some years ago they had to give back the cartridges from home. but I do not trust in that!  

EDIT: "The structure of the Swiss militia system stipulates that the soldiers keep their own personal equipment, including all personally assigned weapons, at home (until 2007 this also included ammo[3])." http://en.wikipedia.org/wiki/Military_of_Switzerland
http://www.swissinfo.ch/eng/Specials/Gun_debate/Background/Archives/Soldiers_can_keep_guns_at_home_but_not_ammo.html?cid=970614