# Why Etchd A timestamp proof shows that some data existed by a certain time, without revealing the data and without anyone having to vouch for it, and Etchd makes these proofs once a minute on Ethereum Classic in the format OpenTimestamps uses. ## Why Timestamp Anything Plenty of disputes come down to what someone had, and when. Two labs both claim a result first. A vendor says the release you shipped was changed after the fact, an auditor asks whether a log file was there before the incident, or the two sides of a contract each remember a different draft. The usual answer is a trusted party, such as a notary, an email server or a cloud provider's file history, any of which can be wrong or come under pressure. Records get lost when a company closes. A proof anchored in a public blockchain needs none of them. With the file, the proof and access to the chain it still checks years later, and the data stays private all along, because the proof commits only to a hash and nobody sees the file until you choose to show it. Generated images, audio and documents are getting hard to tell from real ones. "Is this real" has no easy answer. "Did this exist on 2026-10-22" still does. A timestamp cannot prove a file is authentic, but it does rule out any fake made after the stamp, since there is no way to go back and stamp earlier. A signature records who signed. Keys leak, get stolen or fall to quantum computers, though, and once a key is broken a new forgery looks the same as an old original. A hash anchored under proof of work holds no secret to leak. The proof outlives the keys. ## A Public Record of What Was Real Libraries, newspaper archives and the Wayback Machine keep what was said so later readers can look it up, but we know of none that can show, from its own records, that its copy was never changed. Etchd commits every minute to what a spread of public sources said, anchors that on two proof-of-work chains and publishes the hashes with the headlines and records they cover for anyone to keep. A reader years from now with a copy of a 2026 headline, recording or dataset can check it against the tick that captured it. We think of the tick history as a public good, like a weather record. It is kept for anyone. Most of its readers will be people we never meet. It grows more useful the longer it runs, and when images, audio and text can all be generated, a record of what public sources said at each minute is one of the few things a later reader can lean on. One source can be wrong or slanted, but with several from different countries and kinds of institution a reader can cross-check one against another. Today the ticks cover the front pages of 80 news outlets in every major region, each read every two hours, state-run and independent side by side, from the BBC, NHK and TASS to Meduza, Haaretz and News24. Next to them sit Hacker News, Certificate Transparency logs, the NIST randomness beacon and the ECB's exchange rates. We plan to add more. [What We Publish](https://etchd.app/docs/what-we-publish) keeps the current list with each source's schedule. A tick also works like the newspaper held up in a photo, because it commits to the newest blocks of about 35 chains and to the latest headlines, none of which anyone knew in advance. Quote a tick root inside something you make and the thing dates from after that minute. Stamp it as well and it is pinned from both sides. ## Why OpenTimestamps Writing one hash per transaction to Bitcoin is slow and expensive. Peter Todd started [OpenTimestamps](https://opentimestamps.org/) in 2016 to solve the cost. An OpenTimestamps calendar collects hashes from many people, folds them into a Merkle tree and puts only the root in a Bitcoin transaction, and each person gets a small `.ots` file with the path from their hash to that transaction. Once a proof reaches a Bitcoin block it checks against Bitcoin alone, and the calendar could vanish without harming it. Anyone can run a calendar, since the format is open and the tools are free. A Bitcoin attestation usually arrives hours after you stamp, because calendars batch their transactions and Bitcoin blocks come about every ten minutes. Every minute the hashes stamped, the newest blocks of other chains and our witness captures fold into one root on Ethereum Classic. ## Why Ethereum Classic ### Proof of Work On a proof-of-stake chain validator signatures secure the past, and whoever later gets hold of enough old validator keys can sign a convincing different history. New nodes on those chains start from a checkpoint they trust for that reason (Ethereum calls this weak subjectivity). Proof of work needs no checkpoint. The chain can be checked from block 0 with no trusted party, and rewriting an anchored block means redoing all the work piled on top of it, which no key, stolen or [broken by a quantum computer](https://etchd.app/docs/proofs#proof-of-work), helps with. ### The 2016 Fork In 2016, after the DAO hack, the Ethereum Classic community declined to reverse transactions, and the chain exists because of that decision. It has refused once to rewrite history. For a public record we count that in its favour. ### The Bitcoin Attestation Ethereum Classic is mined with Etchash and Bitcoin with SHA-256, by different miners. Every hour Etchd stamps its tick roots through the public OpenTimestamps calendars, and each proof gains a Bitcoin attestation through [the Bitcoin bridge](https://etchd.app/docs/bitcoin), while in the other direction each tick records the newest Bitcoin block. A reorg on one chain or a break in one algorithm leaves the other proof standing. ### Cost At 1 gwei an anchor costs a small fraction of a cent. We send one for every [tick](https://etchd.app/docs/ticks), once a minute, and a stamp reaches the chain within a minute or two. The calendar serves the proof as soon as that block is mined, and a verifier who wants more [confirmations](https://etchd.app/docs/verifying#confirmations) waits about 13 s for each. OpenTimestamps batches for hours because a Bitcoin transaction costs far more. ### EVM Compatibility Anchors are ordinary transactions to a verified contract, which any Ethereum wallet, explorer or library can read, and an EVM contract can check an Etchd proof. The chain shares Ethereum's history back to the 2015 genesis block. No company stands behind it. Etchd adds no token and no account.