Anonymize a text before you paste it into Microsoft Copilot
Paste your text below. Client names, companies, emails, phone numbers and bank details become codes such as NAME-001. Paste the coded text into Copilot, then paste its answer back in the Restore tab: the real names come back on your screen, and Microsoft never received them.
Restoring uses the key of this tab: code your text here first, keep this tab open, then come back with the answer.
Adjust
See the key (it stays in this tab)
The key links each code to the real value. It exists only in this tab's memory: close or reload the tab and it is gone.
connect-src 'none' in its security policy) and loads no analytics. Turn Wi-Fi off once the page has loaded: the tool works just the same. The engine is the one inside the Hidden Tokens app.How it works
1 · Code
Paste a text or drop a file. Names, companies, addresses, emails, phone numbers, bank details, ID and case numbers become codes such as NAME-001 or COMPANY-001. Unknown proper nouns are coded too: when in doubt, the engine codes.
2 · Send the codes
Copy the coded text, or download the coded file, and give it to ChatGPT, Claude, Gemini or Copilot. The AI reasons on the codes: it still knows who did what, not who they are.
3 · Restore
Paste the AI's answer in the Restore tab, in the same browser tab. The codes become the real names again, on your screen only.
Copilot's protection is a contract; coding is a fact
With a work account, Microsoft offers enterprise data protection for Copilot: your prompts are covered by your organisation's agreement and are not used to train the models. That is a real commitment, but it governs what Microsoft does with the data, not whether Microsoft receives it. On a personal account, the consumer terms apply instead.
Coding first changes the question. If the text Copilot receives says COMPANY-001 instead of your client's name, there is nothing to protect on Microsoft's side.
- Code here. Paste the email, the notes or the paragraph, press Code it, and read the result.
- Use Copilot as usual. In the Copilot app, in Edge or in the Microsoft 365 app, ask your question on the coded text.
- Restore here. Paste Copilot's reply into the Restore tab of this same browser tab.
One limit to know: Copilot inside Word, Outlook or Teams can read your documents and mailbox directly, through your Microsoft 365 permissions. This tool protects what you paste; it does not change what Copilot can already open. That part is set by your administrator.
The free tool or the Hidden Tokens app?
This free tool
- One text or one file at a time
- Up to 3,000 words or 1,000 spreadsheet rows
- The key lives in this tab and disappears when you close it
- Word, Excel, CSV and text
The Hidden Tokens app
- Whole folders: the same person keeps the same code in every document
- One key per case file, kept on your computer
- PDF and scanned documents, read on your computer
- Inside Claude Desktop, and in ChatGPT, Gemini and Copilot with the extension
- Industry packs, firm rules and a signed proof of what the AI saw
A word on the word “anonymize”
Strictly speaking, this tool pseudonymizes: each value is replaced by a code that can be reversed with the key. Under the GDPR, pseudonymised data is still personal data for whoever holds the key, which here is you, in this tab. What the AI receives no longer names anyone directly. Clues can remain, such as a job, a town and an age together: the tool warns you when it sees them. Read the result before sending it.
Questions
Does Copilot still understand the coded text?
Yes. The same person keeps the same code, people and companies have different prefixes, and dates and amounts stay readable. Copilot reasons on who did what without knowing who they are.
Isn't Microsoft 365 Copilot already private?
With a work account it comes with enterprise data protection under your organisation's contract. Copilot still receives and processes what you send. Coding first means client names are never in that data at all.
Does it work with Copilot in Word or Outlook?
For text you paste into a Copilot prompt, yes. When Copilot reads a document or an email directly from Microsoft 365, it sees the original: code the file here first and work on the coded copy.
Is this a Microsoft tool?
No. Hidden Tokens is independent and not affiliated with Microsoft. The same tool works with ChatGPT, Claude and Gemini.
Other ways to use the free tool
For whole folders, use the app
Hidden Tokens codes whole case files on your computer with one key, works inside Claude Desktop and in your browser, reads PDFs and scans, and puts the real names back into Word and Excel files.