Subject: [bitcoin-dev] Add a moving checkpoint to the Bitcoin protocol

From: "Kenshiro []" <[email-masked]>
Date: Wed, 31 Jul 2019 12:28:58 +0000

Hi all,

I would like to propose that a "moving checkpoint" is added to the Bitcoin protocol. It's a very simple rule already implemented in NXT coin:

- A node will ignore any new block under nodeBlockHeight - N, so the blockchain becomes truly immutable after N blocks, even during a 51% attack which thanks to the moving checkpoint can't rewrite history older than the last N blocks.

NXT coin has a N value of 720 blocks, like 12 hours of blocks.

To be more conservative, Bitcoin could have a N value of 144 blocks (like 24 hours). So users and exchanges could plan their operations with big amounts of BTC knowing that only after 24 hours a transaction is truly immutable.

Maybe a 51% attack never happens but if it does it would be nice to be 100% sure that history rewrite is limited to only 24 hours.

Regards,