Hidden Tokens Academy

Learn the gesture, not the theory: how to let an AI work on a confidential file without sending it the names, the identifiers or the bank details. Nine short lessons, free, no account, all on an invented case file.

What you will do

Look at a file the way an AI reads it, comments and headers included.
Protect a folder on your own computer, then check the coded copy yourself.
Work with Claude, ChatGPT, Gemini or Copilot on codes, and get the real values back on your machine.
Prove what the AI actually received.

The sample folder

Every exercise uses the same invented case file: a letter in Word (with a header and a comment), a payroll spreadsheet, a services agreement in PDF and the scan of an identity card marked SPECIMEN. Every name, number and company in it is made up. Never practise on a real file, not even "just to try".

Sample folder, English (a fictitious London law firm) .zip · 135 KB
Dossier d'exemple, français (un cabinet fictif à Casablanca) .zip · 137 KB

The lessons

0
What an AI sees of your filesIs it safe to put client data in ChatGPT?3 min
1
Install Hidden Tokens and start the trialHow do I anonymise documents before ChatGPT on Mac or Windows?4 min
2
Protect a folder and check the coded copyHow do I anonymise a Word or Excel file before an AI reads it?5 min
3
Claude on confidential filesHow do I use Claude with confidential documents?4 min
4
ChatGPT, Gemini and Copilot in the browserHow do I anonymise my ChatGPT prompts?4 min
5
Put the real values backHow do I de-anonymise the AI's output?3 min
6
Prove what the AI receivedHow can I check what data an AI received?4 min
7
Your industry: packs and rulesHow do I anonymise legal, HR or medical documents for AI?3 min
8
The final exercise and the badge5 min

What this is, and what it is not

The Academy teaches the tool, with its limits. A coded file is pseudonymised, not anonymous: the key that turns the codes back into names stays on your computer, so under the GDPR the data is still personal data for you. Text typed into an AI outside the browser extension is not covered. The Mac app needs Apple Silicon; the Windows installer is not signed yet, so SmartScreen warns on first launch.

It is not a compliance course (the GDPR, professional secrecy, a team's AI policy) and the badge at the end attests that you did the exercise, nothing more: it is not a certification.