Good morning Filippo,
> Hi!
>
> From the proposal it is not clear why a miner must reference other miners'
> shares in his shares.
> What I mean is that there is a huge incentive for a rogue miner to not
> reference any share from
> other miner so he won't share the reward with anyone, but it will be paid for
> the share that he
> create because good miners will reference his shares.
> The pool will probably become unprofitable for good miners.
>
> Another thing that I do not understand is how to resolve conflicts. For
> example, using figure 1 at
> page 1, a node could be receive this 2 valid states:
>
> 1. L -> a1 -> a2 -> a3 -> R
> 2. L -> a1* -> a2* -> R
>
> To resolve the above fork the only two method that comes to my mind are:
>
> 1. use the one that has more work
> 2. use the longest one
> Btw both methods present an issue IMHO.
>
> If the longest chain is used:
> When a block (L) is find, a miner (a) could easily create a lot of share with
> low difficulty
> (L -> a1* -> a2* -> ... -> an*), then start to mine shares with his real
> hashrate (L -> a1 -> a2)
> and publish them so they get referenced. If someone else finds a block he
> gets the reward cause he
> has been referenced. If he finds the block he just attaches the funded block
> to the longest chain
> (that reference no one) and publishes it without sharing the reward
> (L -> a1* -> a2* -> ... -> an* -> R).
>
> If is used the one with more work:
> A miner that has published the shares (L -> a1 -> a2 -> a3) when find a block
> R that alone has more
> work than a1 + a2 + a3 it just publish (L -> R) and he do not share the
> reward with anyone.
My understanding from the "Braid" in braidpool is that every share can
reference more than one previous share.
In your proposed attack, a single hasher refers only to shares that the hasher
itself makes.
However, a good hasher will refer not only to its own shares, but also to
shares of the "bad" hasher.
And all honest hashers will be based, not on a single chain, but on the share
that refers to the most total work.
So consider these shares from a bad hasher:
BAD1 <- BAD2 <- BAD3
A good hasher will refer to those, and also to its own shares:
BAD1 <- BAD2 <- BAD3
^ ^ ^
| | |
| | +------+
| +-----+ |
| | |
+--- GOOD1 <- GOOD2 <- GOOD3
`GOOD3` refers to 5 other shares, whereas `BAD3` refers to only 2 shares, so
`GOOD3` will be considered weightier, thus removing this avenue of attack and
resolving the issue.
Even if measured in terms of total work, `GOOD3` also contains the work that
`BAD3` does, so it would still win.
Regards,
ZmnSCPxj
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