CHIP 2023-06 Commit Size Of Block

This is a CHIP to add a commitment to the size of the block, directly after the BIP34 height.
Idea originated out of a discussion held yesterday with @bitcoincashautist and @im_uname .

Full proposal in GitLab here:

p.s. Early draft, I’ve yet to add much that is marked TODO right now, and it’s missing the (unviable imo) alternative to modify the header to include the block size, and I need to do some more digging into the coinbases on chain and come up with a reference implementation.

If you have something you think I should correct or add, feel free to let me know in comments.


Big appreciation for taking the time to sort out the discussion and make a concrete take.


I think @cculianu just convinced me that this commitment isn’t needed because it could be handled equally well on the p2p message layer where the size of the block should already be able to be inferred from the payload byte count of a BLOCK message.

That I agree with…

I’ll think a bit more about whether there is any further point in pursuing this CHIP.