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Author Topic: What is the incentive to collect transactions?  (Read 9610 times)
molecular
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October 05, 2012, 10:24:11 PM
 #21

Adding transactions to the block you're working on will slow down your generation rate
The premise is false.  Adding more transactions to the block you're working on does NOT slow down your generation rate.  When generate is scanning hashes, it only hashes the header of the block, which is constant size.  The header contains a hash of the transactions (the Merkle root) and is only updated occasionally.

If necessary I can write code to make nodes prefer not to use a block if it doesn't contain enough of the transactions they know about.  A discouraged block would almost always fail to be included in the main chain, but would be accepted if it did get in.  I doubt this will be necessary, since there's no real advantage for nodes not to include all transactions.

What if the state developed and sold a lot of ASICs that don't include any transaction? If these ASICs are better than anyone's else, then most of miners will use such malicious devices. The state can afford to hire the best scientists and the best engineers to create such ASICs. It can even sell these devices much cheaper than, say, Butterfly Labs. Was the mentioned functionality (rejecting blocks with not enough transaction) implemented?

The ASIC itself doesn't concern itself with block construction, that's done by mining software on host machine. The ASIC only does the dirty hashing work.

As said by Satoshi and also Gavin and others more recently (when that botnet or whatever it was appearead early 2012 mining non-tx block) there are effective ways to deal with such an attack.

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According to NIST and ECRYPT II, the cryptographic algorithms used in Bitcoin are expected to be strong until at least 2030. (After that, it will not be too difficult to transition to different algorithms.)
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October 05, 2012, 11:02:18 PM
 #22

I'm talking about next few years.

If u were a miner what would u choose:
1. Find 1 block every 24 hours with some fees.
2. Find 1 block every 16 hours with no fees.

Why on earth would anyone make this choice?  Are you confused about how mining works?  Here's a hint to get you started: including transactions does not hurt your hash rate.

Heh. It's the 1st time I see a person who can write but can't read.

What if the state developed and sold a lot of ASICs that don't include any transaction? If these ASICs are better than anyone's else, then most of miners will use such malicious devices. The state can afford to hire the best scientists and the best engineers to create such ASICs. It can even sell these devices much cheaper than, say, Butterfly Labs. Was the mentioned functionality (rejecting blocks with not enough transaction) implemented?

Should I rewrite it MORE slowly?  Grin

How about you write it on this planet instead?

In your hypothetical universe where the chip has the telepathic ability to refuse to hash blocks that include transactions, pigs will fly out of unicorn asses.

In this universe, where the ability to get paid for a block is exactly the same thing, as far as the chip is concerned, as being able to include transactions, no one can force this choice on you.

p2pcoin: a USB/CD/PXE p2pool miner - 1N8ZXx2cuMzqBYSK72X4DAy1UdDbZQNPLf - todo
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October 06, 2012, 05:53:13 AM
 #23

There are easier, quicker, cheaper ways to do that...

We'll get rid of all weaknesses one by one. I'm analyzing this one right now.


The ASIC itself doesn't concern itself with block construction, that's done by mining software on host machine. The ASIC only does the dirty hashing work.

It seems to be possible to move "block construction" logic into the chip.
molecular
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October 06, 2012, 12:14:46 PM
 #24

It seems to be possible to move "block construction" logic into the chip.

It's possible to move anything into the chip... however it doesn't make sense because "block construction" is complex and not time-critical.

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October 06, 2012, 12:18:08 PM
 #25

It seems to be possible to move "block construction" logic into the chip.

It's possible to move anything into the chip... however it doesn't make sense because "block construction" is complex and not time-critical.

For the state that wants to shutdown Bitcoin it does make sense.
molecular
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October 06, 2012, 01:00:54 PM
 #26

It seems to be possible to move "block construction" logic into the chip.

It's possible to move anything into the chip... however it doesn't make sense because "block construction" is complex and not time-critical.

For the state that wants to shutdown Bitcoin it does make sense.

Why would they sell the chips, though, instead of simply running them themselves? In that case they might as well use ASIC only for hashing (as would be sensible as argued) because they control the software and can do 0-tx-block-construction on CPU.

Also: please recall my argument that there are possible countermeasures against this which could be employed once the attack commences. This makes the attack impractical (it will fail) and therefore noone will attempt it. Even without actually implementing the countermeasures beforehand, merely the possibility of implementing them on demand is sufficient to avoid this attack.

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March 05, 2013, 10:42:45 PM
 #27


Also: please recall my argument that there are possible countermeasures against this which could be employed once the attack commences. This makes the attack impractical (it will fail) and therefore noone will attempt it. Even without actually implementing the countermeasures beforehand, merely the possibility of implementing them on demand is sufficient to avoid this attack.


can u elaborate on what countermeasures can be taken?  what happened to the Mystery Miner?
molecular
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March 06, 2013, 10:35:05 PM
 #28


Also: please recall my argument that there are possible countermeasures against this which could be employed once the attack commences. This makes the attack impractical (it will fail) and therefore noone will attempt it. Even without actually implementing the countermeasures beforehand, merely the possibility of implementing them on demand is sufficient to avoid this attack.


can u elaborate on what countermeasures can be taken?  what happened to the Mystery Miner?

Wow, this was a while ago... I cant even remember the thread in which the countermeasures (I guess we're talking about a "0-tx-block" attack) have been discussed.

One idea (the one that stuck in my memory until now) was to reject blocks that contain substantially less transactions than are currently in the set of transaction awaiting a block from the point of view of each node/miner. This would avoid falsely rejecting blocks in cases where a block is found shortly after another one and so there are no (or a low number of) transactions or in cases where there are no or not many transaction for other reasons.

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March 06, 2013, 11:23:44 PM
 #29

This undead thread is fundamentally flawed in any and all assumptions that are being made as a basis of argument.

1:

Adding transactions to the block you're working on will slow down your generation rate. What prevents the majority of generating nodes from ignoring broadcasted transactions and making the network unreliable?

Theymos made an incorrect assumption, hash rate is in no way affected by the inclusion or non-inclusion of transactions, there is no advantage to not including transactions. There may have been a very small bit of CPU used in the CPU solo mining days when creating a new merkle tree when a new transaction was received, but these days where multiple pools have over 4TH, the number of included transactions in no way impacts the hashing that miners are doing - they don't even know how many transactions are in the block data that is being hashed.

Secondly, even if 50% of the blocks included no transactions, Bitcoin would keep on working. There was already a "mystery miner" that was using a botnet that didn't include transactions, and his 10% of the hashrate was merely a curiosity.

If a bad actor has more than 50% of the hashrate required to deny transaction inclusion on more than half the blocks mined, there is a much bigger problem, as they already have enough hashrate to do a 51% attack and can cause more problems by rewriting block history, double spending and erasing blocks. Bitcoin relies on a majority of mining being good, there is little defense against a majority hashrate attack.

Finally there is no motivation for this. If a pool operator was doing something against the interests of Bitcoin, it would be known and miners would leave. Not including transactions would be passing up considerable earnings.




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