Uniquely identifying forked chains
3 messages, 28 Aug 2015. Started by gladoscc.
gladoscc, Matt Whitlock, Jorge Timón
There has been discussion of using the genesis block hash to identify chains in BIP 21 (bitcoin:// URI scheme). However, this does not allow identification between blockchain forks building upon the same genesis block. While many see this as undesirable, I think it is inevitable that this will eventually happen at some point, and think it is best to build systems redundantly.
I propose identifying blockchains for BIP 21 and any other relevant needs through:
1) the genesis block hash for a new chain, or 2) a hash of the genesis block hash, concatenated with block hash(es) of fork point(s) for a fork chain
This would support forks, forks of forks, forks of forks of forks, etc while preserving a fixed length chain identifier.
If a user wants to specify "whatever chain is the longest with PoW", they would use (1). In times where multiple chains are coexisting and being actively mined, a user can use (2) to specifically identify a chain.
Thoughts?
Why would you use a hash of hashes? Wouldn't it be simpler and just as effective to use either:
1) the genesis block hash, or 2) the block hash of the first block in a fork?
Every block hash in a chain implicitly subsumes the genesis block hash of that chain, so there's no need to incorporate the genesis block hash again.
On Saturday, 29 August 2015, at 1:27 am, gladoscc via bitcoin-dev wrote:
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> There has been discussion of using the genesis block hash to identify > chains in BIP 21 (bitcoin:// URI scheme). However, this does not allow > identification between blockchain forks building upon the same genesis > block. While many see this as undesirable, I think it is inevitable that > this will eventually happen at some point, and think it is best to build > systems redundantly. > > I propose identifying blockchains for BIP 21 and any other relevant needs > through: > > 1) the genesis block hash for a new chain, or > 2) a hash of the genesis block hash, concatenated with block hash(es) of > fork point(s) for a fork chain > > This would support forks, forks of forks, forks of forks of forks, etc > while preserving a fixed length chain identifier. > > If a user wants to specify "whatever chain is the longest with PoW", they > would use (1). In times where multiple chains are coexisting and being > actively mined, a user can use (2) to specifically identify a chain. > > Thoughts?
On Fri, Aug 28, 2015 at 10:15 PM, Matt Whitlock via bitcoin-dev <bitcoin-dev@lists•linuxfoundation•org> wrote:
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> Why would you use a hash of hashes? Wouldn't it be simpler and just as effective to use either: > > 1) the genesis block hash, or
If it's a new chain, we're talking about a "spinoffs" https://bitcointalk.org/index.php?topic=563972.0
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> 2) the block hash of the first block in a fork?
Yes, this seems like the best solution in the schism hardfork case. What both sides of a schism hardfork would want is to avoid hurting bystander users who can't tell the difference between the old and the new currency/chain.
I should extend BIP99's section on schism hardforks. Anybody else is welcomed to propose changes to the BIP draft, just PR to this branch:
https://github.com/jtimon/bips/tree/bip-forks
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> Every block hash in a chain implicitly subsumes the genesis block hash of that chain, so there's no need to incorporate the genesis block hash again. > > > On Saturday, 29 August 2015, at 1:27 am, gladoscc via bitcoin-dev wrote: >> There has been discussion of using the genesis block hash to identify >> chains in BIP 21 (bitcoin:// URI scheme). However, this does not allow >> identification between blockchain forks building upon the same genesis >> block. While many see this as undesirable, I think it is inevitable that >> this will eventually happen at some point, and think it is best to build >> systems redundantly. >> >> I propose identifying blockchains for BIP 21 and any other relevant needs >> through: >> >> 1) the genesis block hash for a new chain, or >> 2) a hash of the genesis block hash, concatenated with block hash(es) of >> fork point(s) for a fork chain >> >> This would support forks, forks of forks, forks of forks of forks, etc >> while preserving a fixed length chain identifier. >> >> If a user wants to specify "whatever chain is the longest with PoW", they >> would use (1). In times where multiple chains are coexisting and being >> actively mined, a user can use (2) to specifically identify a chain. >> >> Thoughts? > _______________________________________________ > bitcoin-dev mailing list > bitcoin-dev@lists•linuxfoundation•org > https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev