Browsercoin Dev Update: Fast sync! new users can start mining in seconds instead of ~20 minutes on a fresh device!

Hello everyone, I found this latest development in the Browsercoin Experiment quite interesting and wanted to share it with the community here.

Until yesterday, opening browsercoin for the first time meant downloading and re-verifying the entire chain (~26,000 blocks) before you could mine. On a decent machine that was ~20 minutes of staring at a progress bar. That's now gone.

What happens now when you open the site fresh:

1. Your browser downloads just the block headers (~3.6 MB for the whole chain) and checks every one locally: the hash linkage back to genesis, the exact difficulty schedule, timestamp rules, plus spot-checked proof-of-work on a random sample.
2. It fetches a compact snapshot of every balance and verifies it against the state commitment inside the header chain. Every block header commits to a fingerprint of the full ledger inside its proof-of-work so a fake snapshot would require redoing the chain's mining. No server is trusted at any point.
3. You're synced and can mine. In testing this takes seconds usually well under a minute even on slower hardware.
4. The full block history still downloads quietly in the background (you'll see a "history N%" pill in the top bar). Once it finishes, your tab is a complete archival node, exactly like before it can serve the chain to other browsers, show full history, everything.

So the deal is: everyone is still a full node you just don't have to verify the entire history before your first hash. Verification that used to block you now happens behind you, and if anything ever fails the check, your node throws it all away and re-syncs from genesis the old way.

Credit to pijemcolu for pushing on this the suggestion and it turned out the chain design already supported something stronger: verifying the snapshot immediately against proof-of-work.