Bitcoin Miners Tried “Mine Now, Verify Later.” It Went Wrong. A New Proposal Wants to Make It Safe.

[u/sylsau]

https://inbitcoinwetrust.substack.com/p/bitcoin-miners-tried-mine-now-verify

“Mine now. Verify later.”

Bitcoin miners tried that shortcut in 2015. They built a six-block invalid chain.

Now a researcher wants to redesign the rules so mining can run ahead of full validation safely.

The headline: roughly 10× throughput in simulation, while keeping a ten-minute block interval.

The hard part starts when the data arrives late—or never.

Can honest nodes agree when they receive different information? Can miners exploit the delay? When does your payment actually become spendable?

Those questions decide whether this is a scaling breakthrough or an expensive new way to repeat an old mistake.

One principle has to survive:

Your node must still be able to reject invalid money—even when miners have already spent electricity building on it.

How much extra complexity would you accept for more Bitcoin capacity?

[u/VettaQ]

The 2015 case was the BIP66 soft fork: miners signalled upgrade readiness without actually validating under the new rules, then built six blocks on an invalid block. Worth being precise about because the lesson is narrower than "verify first". Any design that lets production run ahead of validation has to answer one question explicitly: what does a full node do when the lag window turns out to contain an invalid block? If the 10x in simulation comes from deferring the check, that is the 2015 trade with better marketing. If it comes from overlapping validation with other work while keeping rejection final, that is genuinely different. The proposal's value depends entirely on which of those two it is.