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Bitcoin => Bitcoin Discussion => Topic started by: mcqueenorama on June 16, 2011, 04:59:57 PM



Title: Questions from Hacker Group
Post by: mcqueenorama on June 16, 2011, 04:59:57 PM
I talked at a hacker group here in Mountain View last night.  They were very interesting.  They have a few questions that I couldn't answer:

* Who gets the txn fees that are put on small txns?  I sent a small txn to another wallet of my own, and was charged a small fee.  Who got that fee?  I did not get it, and nobody else took part in the txn!  Where did that money go?  Who got that money?

* How is balance within a coin tracked? - The transaction list is a clear concept as I presented it, but I present it as if the bitcoin were an atom which is not true.  How is subdivision of a bitcoin handled?  The balance and the ownership of each fraction will need to be tracked and checked for each txn and if there are many small ones they would be scattered all along the block chain which would make validating a single txn inefficient.

* selfish blocks - A node could pretend to receive no other txns except its own txn 0, and simply focus on hashing.  This would be an unfair an advantage, though a small one. Sounds feasible but not scary.

* Takeover the irc server and direct all new peers to a darknet of their own controlled nodes so they can establish their own dominant block chain. 

About the talk: It was a South Bay hacker group called DC650 at the Hacker Dojo.  I was referred to them by the folks from the SF hacker group where I spoke on Sunday.  I did a speech for over an hour, and then we did questions for another hour.  It all went very well.


Title: Re: Questions from Hacker Group
Post by: error on June 16, 2011, 05:08:11 PM
Transaction processors receive the transaction fees when they successfully create the block containing the transaction.

Look at blockexplorer.com to see the blocks and how coins are constructed and deconstructed.

A node that refuses to incorporate transactions would lose out on the transaction fees.

And the IRC server could be compromised, though Bitcoin does not require it.


Title: Re: Questions from Hacker Group
Post by: Lemmih on June 16, 2011, 09:38:40 PM
* Who gets the txn fees that are put on small txns?  I sent a small txn to another wallet of my own, and was charged a small fee.  Who got that fee?  I did not get it, and nobody else took part in the txn!  Where did that money go?  Who got that money?

The miner who processed your transaction got the transaction fee.

* How is balance within a coin tracked? - The transaction list is a clear concept as I presented it, but I present it as if the bitcoin were an atom which is not true.  How is subdivision of a bitcoin handled?  The balance and the ownership of each fraction will need to be tracked and checked for each txn and if there are many small ones they would be scattered all along the block chain which would make validating a single txn inefficient.

A "bitcoin" is defined as 100,000,000 base units. Ownership (the right to transfer the base units) is tracked by the transactions.

* selfish blocks - A node could pretend to receive no other txns except its own txn 0, and simply focus on hashing.  This would be an unfair an advantage, though a small one. Sounds feasible but not scary.

I'm not sure what you mean. Miners are not obligated to include any transactions and it does happen that they only include transactions that have a fee.

* Takeover the irc server and direct all new peers to a darknet of their own controlled nodes so they can establish their own dominant block chain. 

This is only an issue with the mainline client. Additionally, you'd still have to create blocks with the current difficulty which is quite hard.



Title: Re: Questions from Hacker Group
Post by: davout on June 16, 2011, 09:43:23 PM
A "bitcoin" is defined as 100,000,000 base units. Ownership (the right to transfer the base units) is tracked by the transactions.
There is no such thing, the precision can theoretically be increased.


Title: Re: Questions from Hacker Group
Post by: Lemmih on June 17, 2011, 10:46:59 AM
A "bitcoin" is defined as 100,000,000 base units. Ownership (the right to transfer the base units) is tracked by the transactions.
There is no such thing, the precision can theoretically be increased.

In the current version of the protocol, there most certainly is such a thing. That it can be changed in newer versions doesn't change that.


Title: Re: Questions from Hacker Group
Post by: davout on June 17, 2011, 11:32:32 AM
In the current version of the protocol, there most certainly is such a thing. That it can be changed in newer versions doesn't change that.
We are basically saying the same thing


Title: Re: Questions from Hacker Group
Post by: mcqueenorama on June 19, 2011, 07:03:36 AM
Thanks guys