Zero-Width Text Steganography

Overview

Zero-Width Text Steganography hides a secret message inside ordinary text using invisible Unicode characters. The visible text looks completely normal — no extra spaces, no unusual symbols — but it secretly carries a hidden payload that only this tool (or anyone who knows the technique) can extract.

How It Works: Zero-Width Morse Code

The tool uses three specific Unicode characters that take up zero display width — they exist in the text but render as nothing on screen:

  • U+200B (zero-width space): character separator in Morse code
  • U+200C (zero-width non-joiner): the Morse dot (short signal)
  • U+200D (zero-width joiner): the Morse dash (long signal)

To hide a message, the tool first converts the hidden text into Morse code, then replaces every dot, dash, and separator with the corresponding invisible character. This sequence is then inserted between the "start text" and the "end text" you provide. The recipient sees only the two visible parts joined together, but the invisible sequence sits between them.

What the Output Looks Like

Start text: Meet me
Hidden text: 10:00
End text: there

Visual output: Meet me there
Actual content: Meet me[invisible sequence]there

Anyone who reads the visible message sees "Meet me there." But paste the full text into decryption mode and the tool pulls out "10:00."

Platforms That May Strip Zero-Width Characters

The hidden data survives copy-paste through most plain-text environments, but some systems actively remove invisible characters:

  • Rich text editors (Google Docs, Notion): may strip non-printing characters on paste
  • Plain-text form fields and databases: some sanitize non-printable characters
  • Certain social platforms: some platforms' backends actively clean zero-width characters from posts
  • Code formatters: lint and format tools may remove zero-width characters from strings

Test in your target platform before assuming the hidden data will survive.

How Decryption Works

Switch to decryption mode, paste the text, and the tool scans for the first continuous sequence of zero-width characters. It converts them back from Morse code to readable text. If the text contains no zero-width characters, the tool shows "No zero-width characters detected."

If the source text was converted somewhere along the way (copied from HTML, exported from a PDF), the invisible characters may already be gone — an empty decryption result means the data was lost in transit, not that the tool failed.

Security Limits

Zero-width steganography provides concealment, not encryption. Anyone who knows this technique — or who uses any Unicode analyzer — can decode the hidden content with ease. This tool is suitable for fun hidden messages, invisible watermarking, and covert notation. It is not suitable for protecting genuinely sensitive information.