NXT :: descendant of Bitcoin - Updated Information - page 221.

ChuckOne

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Quote from: CIYAM on March 21, 2014, 11:57:43 AM

[...] "penalty" approach (as it might actually *help* with this - the simpler the algo the harder to game IMO).

I do not see, why penalty worsens the situation when trying out 100000000000000000000000000 combinations of raw transactions and potential blocks?

mthcl

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Quote from: ChuckOne on March 21, 2014, 11:57:34 AM

Quote from: mthcl on March 21, 2014, 11:51:32 AM

1) each block has its own forging queue
2) the network draws from the queue until it is depleted and creates a new one
3) the network considers all accounts of the queue as equally good

Then, if we decide on all queue at once, the algorithm should be changed, because this way you'll not obtain the "correct" forging probabilities (all k_i's are different, right?). Think of a situation when there is an account with 50% of all NXT, and limit=100. Normally this account would forge every second block, but under this approach, it will only forge every 100th.

Quote

Do you mean 2) or 3) ?

2

CIYAM

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Ian Knowles - CIYAM Lead Developer

Quote from: ChuckOne on March 21, 2014, 11:55:39 AM

The point is that an attacker might find a clever combination (trying enough of them out) to control a large enough row.

And this is the *concern* that I have always had about the "penalty" approach (as it might actually *help* with this - the simpler the algo the harder to game IMO).

ChuckOne

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Quote from: mthcl on March 21, 2014, 11:51:32 AM

1) each block has its own forging queue
2) the network draws from the queue until it is depleted and creates a new one
3) the network considers all accounts of the queue as equally good

Then, if we decide on all queue at once, the algorithm should be changed, because this way you'll not obtain the "correct" forging probabilities (all k_i's are different, right?). Think of a situation when there is an account with 50% of all NXT, and limit=100. Normally this account would forge every second block, but under this approach, it will only forge every 100th.
[/quote]

Do you mean 2) or 3) ?

msin

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Quote from: Passion_ltc on March 21, 2014, 02:06:41 AM

Just a few more days until I come back. Is there anyone willing to pay the money for NXT.org?

I canceled 7 domains regarding the Nxt-Ecosystem. After I come back I will concentrate on quality work. Because this is what Nxt needs right now. So please respond to the question above.

Also I want to redirect NXTarea.com to http://mynxt.org/, Mario is that okay for you?

After a few months I would also cancel this domain then, at this point the users should know that mynxt.org is the new landing page.

wesleyh, I'm not following everything right now. But you mentioned something like client-side-verification at http://nxtra.org/nxt-client-trustless/ . Is that also possible for tipNXT.com (not working right now, because I don't have a server for the client)?

So that someone can type in the wallet password to send the money, but it won't get send to the server. Sure there need to be HTTPS then. But will this makes tipNXT 100% secure?

What if someone hack the server and change the code. Is it possible to create a hash or checksum (with php and crojobs!) of the critical .php files and upload them somewhere on an external site?

Looking forward to having you back Passion_ltc definitely miss your web projects, they were all good!

ChuckOne

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Quote from: mthcl on March 21, 2014, 11:47:18 AM

Quote from: ChuckOne on March 21, 2014, 11:42:01 AM

Quote from: mthcl on March 21, 2014, 11:40:47 AM

But I still don't understand, what advantage the attacker obtains by creating these smaller accounts? Why not just sit on his big account and wait?

Creating blocks in a row is the major threat, if I understand it correctly.

Then there is no point in creating new accounts.

The point is that an attacker might find a clever combination (trying enough of them out) to control a large enough row.

L5Society

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Quote from: 2gen on March 21, 2014, 11:44:41 AM

suddenly much buying power wazup?

why is nxt going up so much on bter, is there something comming up, NEWS?

NXT will break 0.7 soon.?? Huge lift of

Not sure about the current market dynamics, but...

Bitcoin currently has a 11% inflation rate, in terms of supply. NXT has 0%. If the ratio of bitcoin market cap to NXT market cap were to stay the same, NXT price (denominated in BTC) would appreciate by 11.11% in 2014, 10% in 2015, 9.09% in 2016, 4.17% in in 2017, and 4.00% in 2018. Source: https://en.bitcoin.it/wiki/Controlled_supply

Food for thought.

mthcl

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Quote from: ChuckOne on March 21, 2014, 11:46:08 AM

Quote from: mthcl on March 21, 2014, 11:43:54 AM

Quote from: ChuckOne on March 21, 2014, 11:34:17 AM

Quote from: mthcl on March 21, 2014, 11:15:27 AM

Can you describe the algorithm of determining the next forgers in terms of the math model? In particular, how exactly this list is updated?

If I read the source correctly, that function will return a sorted list of limit accounts that are able to forge the next block.

In math model:

it is like having not only k₀ but also k₁ and k₂ and ... and k_limit-1 representing the next in the what I would call forging queue.

k₀ is the best, followed by k₁ and so on.

But at the next moment (when the next block is forged) you decide on only one new entry to the queue? Or you wait until the queue is empty and decide on the whole queue then again?

That is yet to be decided.

EDIT:
possibilities if could come up with:

1) each block has its own forging queue
2) the network draws from the queue until it is depleted and creates a new one
3) the network considers all accounts of the queue as equally good

Then, if we decide on all queue at once, the algorithm should be changed, because this way you'll not obtain the "correct" forging probabilities (all k_i's are different, right?). Think of a situation when there is an account with 50% of all NXT, and limit=100. Normally this account would forge every second block, but under this approach, it will only forge every 100th.

CIYAM

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Ian Knowles - CIYAM Lead Developer

Quote from: ChuckOne on March 21, 2014, 11:49:55 AM

Creating blocks in a row that YOU as an attacker controls.

Yes - this is basically what I modeled in code and mthcl in math (not considering the proposed TF but just the existing approach).

Of course any *model* is just that (so it may not be "good enough" to reflect the *reality*).

ChuckOne

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Quote from: mthcl on March 21, 2014, 11:47:18 AM

Quote from: ChuckOne on March 21, 2014, 11:42:01 AM

Quote from: mthcl on March 21, 2014, 11:40:47 AM

But I still don't understand, what advantage the attacker obtains by creating these smaller accounts? Why not just sit on his big account and wait?

Creating blocks in a row is the major threat, if I understand it correctly.

Then there is no point in creating new accounts.

Creating blocks in a row that YOU as an attacker control.

CIYAM

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Ian Knowles - CIYAM Lead Developer

Quote from: mthcl on March 21, 2014, 11:47:18 AM

Then there is no point in creating new accounts.

Yes - that was my understanding from my own modelling.

Still the issue of "randomness" is a key point that I would like to have checked (i.e. how "random" is the block # 1440 blocks in the future).

punkrock

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Quote from: L5Society on March 21, 2014, 11:43:17 AM

Quote from: punkrock on March 21, 2014, 11:32:52 AM

Nxt Blockchain Explorer is not showing transactions. Does someone know why?
The total balance is correct, but the last three incoming transactions are not showen in the list. http://87.230.14.1/nxt/nxt.cgi?action=3000&acc=14467166339972892265

use this instead http://www.mynxt.info/blockexplorer/

Thanks!

mthcl

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Quote from: ChuckOne on March 21, 2014, 11:42:01 AM

Quote from: mthcl on March 21, 2014, 11:40:47 AM

But I still don't understand, what advantage the attacker obtains by creating these smaller accounts? Why not just sit on his big account and wait?

Creating blocks in a row is the major threat, if I understand it correctly.

Then there is no point in creating new accounts.

ChuckOne

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Activity: 364

Merit: 250

☕ NXT-4BTE-8Y4K-CDS2-6TB82

Quote from: mthcl on March 21, 2014, 11:43:54 AM

Quote from: ChuckOne on March 21, 2014, 11:34:17 AM

Quote from: mthcl on March 21, 2014, 11:15:27 AM

Can you describe the algorithm of determining the next forgers in terms of the math model? In particular, how exactly this list is updated?

If I read the source correctly, that function will return a sorted list of limit accounts that are able to forge the next block.

In math model:

it is like having not only k₀ but also k₁ and k₂ and ... and k_limit-1 representing the next in the what I would call forging queue.

k₀ is the best, followed by k₁ and so on.

But at the next moment (when the next block is forged) you decide on only one new entry to the queue? Or you wait until the queue is empty and decide on the whole queue then again?

That is yet to be decided.

EDIT:
possibilities if could come up with:

1) each block has its own forging queue
2) the network draws from the queue until it is depleted and creates a new one
3) the network considers all accounts of the queue as equally good

EDIT 2:
Why do we it at all?
Because not every account will forge, so we need a buffer I a forger is absent.

Come-from-Beyond

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Quote from: Anon136 on March 21, 2014, 10:57:36 AM

there is 1 really solid solution that you arnt going to want to hear

What is it?

2gen

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suddenly much buying power wazup?

why is nxt going up so much on bter, is there something comming up, NEWS?

NXT will break 0.7 soon.?? Huge lift of

CIYAM

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Ian Knowles - CIYAM Lead Developer

Quote from: ChuckOne on March 21, 2014, 11:42:55 AM

Yes, I know.
Nevertheless, you could use the implemented function for both scenarios.

But I think whether we treat that list as "ordered" or not *could* make a difference (so that needs to be considered).

This ends up being important to the "lottery" AT (and others that might follow it) as we need to be confident of the "randomness" of "tickets".

mthcl

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Quote from: ChuckOne on March 21, 2014, 11:34:17 AM

Quote from: mthcl on March 21, 2014, 11:15:27 AM

Can you describe the algorithm of determining the next forgers in terms of the math model? In particular, how exactly this list is updated?

If I read the source correctly, that function will return a sorted list of limit accounts that are able to forge the next block.

In math model:

it is like having not only k₀ but also k₁ and k₂ and ... and k_limit-1 representing the next in the what I would call forging queue.

k₀ is the best, followed by k₁ and so on.

But at the next moment (when the next block is forged) you decide on only one new entry to the queue? Or you wait until the queue is empty and decide on the whole queue then again?

Come-from-Beyond

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Quote from: ChuckOne on March 21, 2014, 10:54:28 AM

So, that attack would go this way:

1) attacker creates N accounts

2) attacker receives M raw transactions

3) attacker tries to find a row of blocks by:

3.0) do until no raw transactions are available
3.1) choose X raw transactions
3.2) is the account forging this block one of the N accounts?
3.3) if yes, go to 3.1) and remove X transactions
3.4) if no, go to 3.1) and choose another selection of raw transactions

4) if no combination will lead to the desired output => attacker creates his own raw transactions, go back to 3)

5) choose longest row and submit it to the network

Is that the attack vector you have in mind?

Something like that. Different variations r possible.

L5Society

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Quote from: punkrock on March 21, 2014, 11:32:52 AM

Nxt Blockchain Explorer is not showing transactions. Does someone know why?
The total balance is correct, but the last three incoming transactions are not showen in the list. http://87.230.14.1/nxt/nxt.cgi?action=3000&acc=14467166339972892265

use this instead http://www.mynxt.info/blockexplorer/

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