How do I prove a file existed on a certain date?
This is the oldest question in creative work and the internet made it urgent: any file can be copied, and the copy carries no date. Here are the ways people answer it, honestly ranked, including the one you can do without us.
The options
Email it to yourself. The “poor man's copyright”. It proves almost nothing: mail headers are editable, and a court has no way to know the attachment was not swapped. Do not rely on it.
A notary. A notarised statement with the file's hash is strong evidence in most jurisdictions. It costs money and a visit per document, so people do it for a finished album, not for every draft.
Government copyright registration. Where it exists (the US, among others) it has legal effects nothing private can match — presumptions, statutory damages, standing to sue. It costs a fee and weeks, applies to what the office accepts as copyrightable, and for AI-assisted work requires disclaiming the generated parts. If you can, do it for anything you would litigate over.
A blockchain timestamp. Compute the file's hash, get that hash into a block of a public chain, keep the proof. Anyone, forever, can recompute the hash from the file and confirm the block's date. It proves existence at a date — not authorship, not ownership — costs nothing or nearly nothing, and scales to every draft. This is the one a registry like ours automates.
Doing it yourself
You do not need us for the bare timestamp. OpenTimestamps is a free, open protocol that batches hashes into the Bitcoin chain; the client is a command line or a web page, and it hands you a .ots proof file to keep next to the original. If all you want is a date on a hash, that is a fine answer and we say so.
What a registry adds
A timestamp on a bare hash says a number existed. It does not say what the number is a fingerprint of, who claimed it, under what name, or what they said they contributed. A registry writes those onto a card first — fingerprint, attribution, dates, contribution, rights declaration — and timestamps the card. Then it gives you a page other people can read, a badge, a version chain between drafts, a binding to a character if the work belongs to one, and a Proof Pack that reproduces the whole verification offline. Ours anchors nightly to Arbitrum One and publishes the verification steps so you never need to trust the platform; the three-act diagram shows the recomputation.
Whichever you pick
Keep the original file, unchanged, with the proof. Every method above vouches for a hash; none of them can vouch for a file you no longer have. And write down, at the time, what you did — a date on a file is worth much more with a contemporaneous account of how it came to exist.
怎麼證明一個檔案在某一天就已經存在？
這是創作領域最老的問題，網路讓它變得急迫：任何檔案都能複製，而副本上沒有日期。以下是人們回答這個問題的幾種方式，照實排序，包括那個不需要我們就能做的。
選項
寄 email 給自己。所謂「窮人的著作權」。幾乎什麼都證明不了：郵件標頭可以改，法院也無從知道附件沒被換過。別依賴它。
公證。載明檔案雜湊的公證聲明，在多數法域都是強證據。每份文件都要花錢跑一趟，所以人們拿它處理做完的專輯，不會每張草稿都去。
政府著作權登記。有這個制度的地方（美國等），它的法律效果沒有任何私人手段比得上——推定、法定賠償、起訴資格。要規費、要等幾週、只受理該機關認定可著作的內容，AI 協作作品還要聲明排除生成的部分。做得到的話，任何你可能為它打官司的東西都去登。
區塊鏈時間戳。算出檔案雜湊，把雜湊放進公開鏈的某個區塊，留好證明。任何人、永遠，都能從檔案重算雜湊、核對區塊日期。它證明某天已存在——不證明創作、不證明所有權——幾乎免費，每張草稿都做得起。這是登錄簿這類服務自動化的那一種。
自己動手
單純要時間戳，不需要我們。OpenTimestamps 是免費的開放協定，把雜湊批次寫進比特幣鏈；客戶端是命令列或一個網頁，會給你一個 .ots 證明檔，放在原檔旁邊。如果你要的只是替一個雜湊蓋日期，這是好答案，我們照實說。
登錄簿多做了什麼
單純雜湊上的時間戳只說「某個數字存在過」。它不說這個數字是什麼的指紋、誰主張的、用什麼名字、聲稱貢獻了什麼。登錄簿先把這些寫到一張卡片上——指紋、署名、日期、貢獻、權利聲明——然後對卡片蓋時間戳。接著給你一個別人讀得懂的頁面、一枚徽章、草稿之間的版本鏈、作品若屬於角色的綁定，以及一份能離線重現整套查驗的 Proof Pack。我們每晚錨定到 Arbitrum One，並公開查驗步驟，所以你永遠不必信任平台；三幕圖解畫出重算過程。
不管選哪一種
原始檔案原封不動，和證明放在一起。上面每一種方法替雜湊作證，沒有一種能替你弄丟的檔案作證。而且當下就把你做了什麼寫下來——檔案上的一個日期，配上一份同時期的來歷說明，價值高得多。
Questions常見問題
Does a blockchain timestamp prove I am the author?區塊鏈時間戳能證明我是作者嗎？
No. It proves a specific file existed at a date. Authorship is a separate claim; a registry record adds your stated attribution and contribution to the timestamped card, which is evidence of what you claimed and when, not proof that the claim is true.
不能。它證明某個檔案在某一天存在。作者身分是另一個主張；登錄簿的紀錄把你聲明的署名與貢獻加進被蓋章的卡片，那是「你在什麼時候主張了什麼」的證據，不是主張為真的證明。
Which chain do you use, and can I verify without you?你們用哪條鏈？不靠你們也能查驗嗎？
Arbitrum One, nightly. The record, its proof path and the transaction are in the Proof Pack; the verification steps are published, and the verify page recomputes them for any fingerprint you paste.
Arbitrum One，每晚一次。紀錄、證明路徑和交易都在 Proof Pack 裡；查驗步驟公開，查驗頁對任何貼上的指紋都會重算。
Is the file itself put on the chain?檔案本身會上鏈嗎？
Never. Only a 32-byte root of that night's fingerprints goes on chain. The file stays with you; whether it is shown on your public page is a separate switch.
從不。上鏈的只有當晚所有指紋算出的 32 位元組樹根。檔案留在你這裡；要不要顯示在公開頁是另一個開關。