Hidden Tokens / Academy / Lesson 2

Protect a folder and check the coded copy

Lesson 2 of 9 · 5 min · app 0.14.4 · connector 2.42.0

Before you start

You need the Hidden Tokens app on a Mac with Apple Silicon (macOS 13 or later) or on Windows 10 or 11, 64-bit. There is no version for Intel Macs. The 14-day trial starts with your first coded file, with no account and no card.

On Windows, the installer is not signed with a Windows certificate yet: on first launch, SmartScreen says "Windows protected your PC". Click More info, then Run anyway. The app installs for your user only, without administrator rights.

Step by step

1. Create an empty practice folder

   Install Hidden Tokens from the download section if you have not yet (Mac with Apple Silicon, or Windows 10 and 11). Then create an empty folder, for example Academy practice in your Documents. Unzip the Academy sample folder somewhere else, on your Desktop for instance: you will drop its files in a moment.

   Done

2. Watch the folder

   Click the Hidden Tokens icon in the menu bar (Mac) or the notification area (Windows), choose Watch a folder…, select Academy practice and click Watch. The app confirms with Folder watched. On a Mac, macOS may ask whether Hidden Tokens can access your Documents folder: accept, it is the app that reads your files, not the AI.

   Done

3. Set the code language to English, before the first file

   From the same menu, choose Open dashboard. On the card of your folder, open Settings and set Code language to English. Do it now: the language is fixed by the folder's key at the first coded file. With English, the codes read NAME-001, and English letters are read as English.

   Done

4. Drop the four files into the folder

   Drag the four files of the sample folder into Academy practice. Within about ten seconds a Hidden-Tokens subfolder appears, with the coded copies: their names end in -anonymise. The letter gives a coded .docx (and a .md text version), the payroll a coded .xlsx, the PDF contract a coded .md. Your original files are never modified.

   Done

5. Search the coded letter for what should be gone

   Open the coded letter, 01-letter-to-client-anonymise.docx, and search it (⌘F on a Mac, Ctrl+F on Windows) for Kettleby, the name in the page header: nothing should answer. Search for 900418, the end of the mobile number hidden in the comment: nothing should answer either. Then GB82, the start of the IBAN. Where they were, you now read codes such as NAME-001 or IBAN-001.

   Done

6. Search the coded payroll

   Open the coded payroll in the same subfolder and search for Wrenfield: nothing. The names, National Insurance numbers, IBANs and dates of birth are codes. The salaries are still readable: once the people are codes, a salary no longer says whose it is. If the figures themselves must stay hidden, change the folder's Numbers setting before coding.

   Done

7. Find what stays readable on purpose

   Open 03-services-agreement-anonymise.md with a text editor (TextEdit, Notepad). The parties and signatories are codes, but the fee, £48,500, is still there. This is the limit to know: an amount written in the body of a contract or a PDF stays readable, whatever the Numbers setting. If the amount itself is the secret, do not give that document to an AI as it is.

   Done

8. Notice the file that was not coded

   The identity card scan, 04-id-card-scan.jpg, has no coded copy: a watched folder codes Word, Excel, CSV, text and PDF files that contain text, not images or scanned PDFs. A scan is read on your computer from Claude Desktop, with a proofreading step (lesson 3). Until then, it does not go to an AI.

   Done

What can go wrong

• No Hidden-Tokens subfolder after a minute. On a Mac, macOS may still be waiting for your answer to its access question: until you accept, nothing is coded. Accept, then choose Watch a folder… again, or quit and reopen the app.
• The dashboard says "Stopped". The folder's connector is not answering: quit and reopen the Hidden Tokens app.
• You searched the original instead of the copy. The originals keep every name, by design. Open the files whose names end in -anonymise, inside Hidden-Tokens.
• The codes read NOM-001 instead of NAME-001. The code language was still on Auto (French codes) when the first file was coded, and the key keeps that choice. It is harmless for this exercise; for a real English-language folder, set English before dropping anything.
• Ordinary English words became codes, sometimes even in a file name. The engine still over-codes some English words it does not know. It errs on the side of hiding; tell us when it gets in the way.
• A label on your screen differs from this page. The app changes faster than this page: trust your screen and tell us.

✓ Lesson done: every step ticked and every answer right. Your progress stays in this browser only.

Written for app 0.14.4 and connector 2.42.0 on 27/10/2026. Not yet replayed on screen on Mac and Windows: if a label differs from what you see, trust your screen and tell us.