Check a record against Bitcoin
Every photograph and diary entry recorded in rm8tes is hashed, and those hashes are gathered hourly into a single fingerprint that is timestamped into the Bitcoin blockchain. This page checks one record against that blockchain.
The check runs entirely in your browser. rm8tes serves two small files and is not told the answer; the block itself is read from two independent public block explorers. Nothing on this page relies on rm8tes being truthful.
A record hash is 64 letters and numbers. You will find one under every record in section 5 of an rm8tes evidence pack, printed as = record hash, and in the QR code beside it.
Both files together let you re-run this check with the standard OpenTimestamps client instead of trusting this page: ots verify <file>.bin.ots. It is free and open source, talks to the calendars and the blockchain directly, and does not contact rm8tes.
What this proves
A Bitcoin block cannot be altered after the fact without redoing every block mined since. So if the fingerprint covering a record is inside a block, that record existed before that block was mined — and no amount of later argument between a tenant and a landlord can move it.
What it does not prove. That the photograph shows what it claims to show, that the place is the place, or that anybody was honest. A timestamp establishes when a record existed and that it has not changed since — nothing more. rm8tes records the time its own server received a photograph and, where the phone reported one, a satellite position; both are stated in the evidence pack for what they are.
The chain of reasoning
Each step below is arithmetic you can repeat yourself.
- The record hash is a SHA-256 fingerprint of the record. The evidence pack prints every field that went into it, so you can recompute it from the page and confirm it matches.
- The sibling path folds that hash together with a handful of neighbours, under the scheme used by Certificate Transparency, until it produces the batch fingerprint — the Merkle root. You never see anybody else’s records, only fingerprints of them.
- The OpenTimestamps proof is a published, open-standard chain of operations leading from that root to a Bitcoin block. Following it arrives at a value that must equal the block’s own Merkle root.
- The block is then read from two independent explorers. If its Merkle root is what the proof arrives at, the record was already fixed when that block was mined.
If a record was recorded within the last hour or so, it may not be anchored yet — anchoring runs hourly and a Bitcoin block usually follows within a few hours. That is reported as awaiting a block rather than as a failure.