Mark Friedenbach, a software engineer, formerly a contractor at NASA-Ames Research Center, and an independent Bitcoin protocol developer has claimed that Bitcoin scaling can be increased without a hard fork. According to a transcript of his presentation at the Scaling Bitcoin workshop, he said that “forward blocks,” could essentially help increase BTC’s block size without a hard fork.
He further explained that they want to be able to scale the bitcoin blockchain on a chain in a manner that an upgraded node will still be able to view the fresh transactions that happened, even if there’s some gap in receiving them. This can be achieved as a soft-fork to bitcoin.
About Forward Blocks
According to Mark Frienenbach, forward blocks appeared because of proof-of-work. The change of proof-of-work could be achieved as a soft-fork mixes with mechanisms for soft-fork implementation of privacy-amplifying optional ledgers. It also gives scaling benefits such as:
- Improved censorship resistance through sharding.
- Direct on-chain scaling up to 3584x (for bitcoin specifically)
Moreover, it gives various other benefits such as a linearized block subsidy and the underlying ledger support for future chain enhancements such as confidential transactions and sidechains. In short, a forwards compatible soft fork is a soft-fork for which un-upgraded nodes still accept and process all transactions.
He further goes on to explain that Forward Blocks require different chains with unrelated proof-of-work functions, rather than a single block chain with each block subject to multiple work requirements. This difficulty should non-disruptively transition from the old proof-of-work to the new.
The easiest way to do this is have a sliding block reward that transitions block reward from going primarily to the solver of the old proof-of-work challenge to the new, over of period of time long enough as to prevent mining disruption. This is expressed by a function P(t) ∈ [0,1] which represents the proportion of the block reward that goes to the new proof-of-work miners vs. the old.
Working of “Forward Blocks”
Mark Friedenbach elaborated that Forward Blocks allows different blockchains with separate proof-of-work (PoW) potentials. In short, there is not one blockchain for each block but more than one blockchain.
I do not wish that ‘proof-of-work upgrade’ be interpreted as an adversarial move against the current set of bitcoin/double-SHA256 miners. Rather it is a direct consequence of the design that the forward blockchain requires a new proof-of-work function. A compatible form of salted merge mining is a sufficiently different function to work for this purpose.
This approach could help with the scaling as bitcoin enthusiasts often oppose hard forks because of how hard it can be to do them safely. A few days ago, a research had said that hard forks are hazardous to cryptocurrency stability.
According to this research, hard forks can divide a cryptocurrency into two rival groups. They can destabilize a given cryptocurrency’s value, and inject a low confidence environment in the capacity of a cryptocurrency to survive as a dependable bridge of exchange. So, it is necessary for the cryptocurrency community to improve their governance system and limit the potential for hard forks to occur.
The hard forks create a new blockchain that is different from its original rival—promoting two technologically irreconcilable cryptocurrencies. As such, hard forks may force governance failures that divide cryptocurrency users into two distinct groups: one that accepts a new technological change and one that rejects the status quo.
Mark Friedenbach also stated that the commonly discussed “safe” protocol for increasing the block weight limit. The forced hard fork moves transactions into a saved extension block with a greater total limit or other consensus changes. After this, it forces the old blocks to go blank. Affirming the authentication of transactions is only possible by upgrading to a client which know the extension block. Un-upgraded nodes are secured from viewing the spend histories because the blocks are empty. To rehab service, they are expected to upgrade.
Speaking to CoinDesk, Mark Friedenbach noted
Forward blocks make that whole argument pointless. We don’t need a hard-fork to scale bitcoin, if and when we decide to do so. It can be accomplished as a soft fork, like SegWit was.
In short, the forward blockchain gets on-chain scaling by raising its per-block total weight limit while keeping a fixed, long time interval. This fulfills the least possible influence on centralization hazards for both competent validators and SPV nodes.