Header chain
Every Bitcoin block starts with an 80-byte header that links to the one before and carries its proof of work. This page checks a proof that the whole header chain from the genesis block is valid under Bitcoin Core's own header rules: each header links to the last, meets its difficulty target, follows the difficulty adjustment every 2,016 blocks, and has a valid timestamp and version. The proof is verified here, on this device, with nothing to trust but the proof system and the published program.
The proof
How it was made: all 975,279 headers, genesis to block 975,278, proved as one run of the published program (RISC Zero 3.1.0) on one NVIDIA RTX PRO 6000 in 59 minutes (2.35 billion cycles), about $2.50 of rented GPU time. New blocks are then proved on an ordinary CPU as one more run chained to it, so the proof follows the tip. The measurement.
Is it the network's chain?
The proof shows a valid chain of headers from genesis. Which chain it is, is its tip. Compare the tip with a source you trust, such as your own node or a block explorer, and paste that source's hash for the same height:
What the proof does and does not say: it proves the headers, the same check a light (SPV) wallet makes, from genesis, under Core's rules. It says nothing about the transactions inside the blocks; the Hazync v2 chain proof does that (Coin check reads it). Below Bitcoin Core's minimum chain work the verdict is DEMO: a valid chain from genesis, but too little work to be evidence of the network's chain.
This proof is checked here, in the browser verifier from the release
(hazync-verify.wasm), against the header-chain program ID
2db34e12cc993dd1edb003f00f85c93d02e0e61208589b57fc5c969d39b3e632. The command-line verifier
checks Hazync chain proofs only: given this file it refuses it, because it is not one.