Re: Bitcoin XT has code which downloads your IP address to facilitate blacklisting
From Bitcoin's point of view, XT's "big blocks" don't exist, so the question of whether or not it can orphan them is moot. Core will continue to work on the longest valid chain, and that doesn't include any chain with blocks greater than 1MB in it.
This is not true according to the original design of Bitcoin. There is no mention of a block size limit in the Bitcoin white paper. The original design was such that (paraphrased):
- Nodes assemble valid transactions into a block and work to find a proof-of-work.
- Nodes express their acceptance of a new block by mining on top of it.
- The longest chain composed of valid transactions is "Bitcoin."
By making it easier for nodes to "express their acceptance of a block" (e.g., for blocks larger than 1 MB via BIP101), we are making it easier for the network to come to consensus according to the original design of Bitcoin.
The block size limit was just a temporary anti-spam measure that crept into the consensus layer inadvertently. Bitcoin was designed to prevent Alice from moving coins without a valid signature, prevent Bob from creating coins out of thin air, and prevent Charlie from spending his coins twice. It wasn't designed to create block space scarcity to push TXs to off-chain solutions.
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The longest valid chain accepted by Core *is* the longest valid chain, by definition.
False. The longest valid chain accepted by Core *is* the longest valid chain accepted by Core, by truism.
The longest chain composed of valid transactions *is* the correct one, according to the Satoshi white paper.