Philippe (Haskoin) and I stumbled upon an interesting idea during the weekend while attempting to improve the reliability of 0-conf transactions. This is the first written description of the Fastchain proposal.
The motivation behind this was originally to have some way to do partial confirmations on mempool transactions, but it soon became evident that we stumbled upon a mechanism that can be used to increase the size of Bitcoin blocks via a soft-fork. I call this system the Fastchain.
The Fastchain is a parallel blockchain where each Fastchain block is merge-mined into the next Bitcoin block. The difficulty of the Fastchain is much lower than that of the main Bitcoin blockchain, with a ratio set at some established constant. Since this is a soft-fork that proposes changes to the Bitcoin consensus protocol, every miner will be required to merge-mine Fastchain, guaranteeing that Fastchain blocks get the full proof-of-work power of the Bitcoin network, therefore similar security guarantees.
Fastchain blocks