Guides
Most of what is written about hidden characters in AI text confuses Unicode steganography with statistical watermarking. These articles separate the two and cite what the vendors actually say.
Invisible Unicode characters: a complete reference
Every category of invisible, zero-width and blank-rendering Unicode character, what each one is legitimately for, and when its presence is a signal that something is hidden in your text.
· 12 min read
Do AI watermarks use invisible characters? No — and here is the evidence
SynthID-Text and Anthropic's Claude watermark are statistical, living in the model's word choices rather than in any added character. Stripping invisible characters has no effect on them whatsoever.
· 9 min read
Invisible prompt injection with Unicode Tags
How the U+E0000 block hides instructions that people cannot see but language models read, why it works, and how to strip it before untrusted text reaches a model.
· 8 min read
Zero-width steganography: how text hides inside text
StegCloak, base-N zero-width encodings and variation-selector channels — the practical schemes for hiding data in a string, their fingerprints, and how detection works.
· 10 min read
Trojan Source: when code does not do what it looks like it does
Bidirectional control characters can reorder how source code is displayed without changing what the compiler sees. How the attack works and how to detect it.
· 6 min read
How to remove invisible characters from text
A practical guide: what to strip, what to replace with a space, what to leave alone, and how to do it without corrupting Turkish, Arabic, Persian, Indic or emoji content.
· 7 min read