Room for sigmabe and croraf

sigmabe

1:08 PM

@croraf, also on bitcointalk there is no reaction...

croraf

1:40 PM

You have to wait a day or two. And write in more looser form than mathematical definitions.

sigmabe

On bitcointalk somebody wants more maths, I don't now what is better.

croraf

True.

But all can be summarized in 2-3 sentences.
You contact more than 50% of miners and bribe them to make a separate chain forking N blocks behind current main head.

For a bribe you offer reward that is several times (let's say 3) larger than the reward for N blocks.

sigmabe

Yes, and I think what is even much better to do it with lended coins.

croraf

In these N blocks you made a lot of large transactions that are finally rewinded.

sigmabe

Combined with the short I think you can get so much profit that worthless hardware is no problem, so the miners can do the attack by their own. And work together is not difficult for the five big mining pools.

croraf

1:51 PM

So you have to put only these 3 sentences on bitcointalk

sigmabe

I think it's better to wait. If posted main ideas at many points and there will come somebody important who understands the problem the next days, I hope.

But the question is, what is if our ideas are correct? Then there would be a attack soon.

croraf

Attack example:
1. Make several large transactions in block X and wait for N blocks.
2. You contact more than 50% of miners and bribe them in real life to make a fork just before block X and to mine on that fork for N blocks.
3. For a bribe you offer reward that is several times (let's say 3x) larger than the reward for N blocks.

Your transactions will be accepted by other party after N blocks, and the rewind will give you back your bitcoins.

----------------------------
After you post that with intriguing title

People will enter discussion.

There won't be attack soon, for example it is hard to contact more than 50% of miners in real life. And second: mining pools will not be part of such attack.

sigmabe

But in my last scenario also the miners can attack, and to work together in 5 mining pools isn't difficult.

croraf

So post this to bitcointalk:
"Attack example:
1. Make several large transactions in block X and wait for N blocks.
2. You contact more than 50% of miners and bribe them in real life to make a fork just before block X and to mine on that fork for N blocks.
3. For a bribe you offer reward that is several times (let's say 3x) larger than the reward for N blocks.

Your transactions will be accepted by other party after N blocks, and the rewind will give you back your bitcoins."

And invent an inriguing title.

You should post as simplest as possible example that is valid.

sigmabe

Could you post your version of the problem? Because it's yours and I can't stop doing my maths thinking comments.

croraf

1:59 PM

I made the example for you here.

Any improvements on the attack come later.

On bitcointalk?

sigmabe

Yes, I think that's best place

croraf

What to put as title

Possible attack on bitcoin currency?

sigmabe

Maybe better would be the bitcoin IRC channel, but I don't no how to handle it.

There should be a title that users see there is a relevant problem

and it's not something which comes everyday by users first heard of bitcoin two minutes before.

Maybe this was the problem of my post.

So I think maybe you should mention large transactions and majority attack in title.

croraf

bitcointalk.org/index.php?topic=2518710.new#new

sigmabe

Thank you.

croraf

2:08 PM

NP

What do you think of my formulation.

Now if someone finds an error you can post your comments if they solve the error.

sigmabe

Yes, I think it's good and it's yours. I think you've understand my position so I think you can also do the moderation.

I hope it works better than my version.

I will go to convince in my post that worthless hardware is no problem for the scenario.

croraf

I know couple of strong developers.

If noone reacts I can contact them.

sigmabe

That would be fine.

croraf

What is currently the biggest objection on this attack that I posted?

1. Hard to find contact 50% of miners

2. Hard to convice them to make a fork, if their equipment cannot mine other coins

sigmabe

Yes.

But first is no problem, because members of the big mining pools can start the attack and the can find contact to 4 other pools easily.

croraf

2:17 PM

But you must contact the pool owner.

And perhaps all large pools control only 40% of power.

sigmabe

Isn't this still correct

buybitcoinworldwide.com/mining/pools

croraf

But this are only pools

You have single miners.

sigmabe

How do they work together in the pool?

If profit is high enough every single miner will follow the pools decision.

Pool owner says: Here is a sure attack scenario with large profits, who wants to do the attack with us?

He also says, I've a large short option on bitcoin, so I can pay you, when bitcoin is down.

Last sentence is rubbish.

Pool owner can bribe the single miners by short options, he holds. This short options have so much value when bitcoin goes down, that the miners would work together.

croraf

6:15 PM

I found that vast majority of miners work in pools.

So you only have to bribe the pools.

@sigmabe

Miners are irrelevant.

You have to bribe the pool owners.

Pool server gives miners template to work on that contains previous block hash.

So indeed it is easy to find and contact >50% of mining power .

So it remains 2. you have to convince them to execute the attack that will lead to bitcoin crash.

sigmabe

6:39 PM

Yes, and I think 2. can be done with a bribe that is very interested for the miners and I think the most interesting for the miners is a short option, so they can destroy the coin and they profit from it.

croraf

8:04 PM

@sigmabe the discussion is going in the wrong direction. Both of you are discussing on personal level. And you posted about shorts that was not needed, I even dont know what they are.

But I still haven't heard the argument against and the post is bloated with replys.

sigmabe

Yes, I think it's time to wait now and hope that there are readers which are interested in it.

I think the short position makes the attack double strong as you see in my calculations in the post.

And you get rid of the technical argument that hardware is worthless afterwards.

I also think it's not good to do personal argumentation and I tried to do it not.

croraf

Cool

sigmabe

What do you mean?

croraf

I mean OK.

I don't know what is short?

sigmabe

It's a possibility to profit from falling prices.

If the price goes to the half the short goes to double.

It's a bit technical, but you can construct this for every assett trading at exchange.

croraf

8:19 PM

I must go to sleep now. Hear you next time

sigmabe

Ok, it's nice to talk to you

The only one who wants to think by himself/herself...

Thanks and good night.

Transcript for

$Mathematics$ Room for sigmabe and croraf