Hidden 26-bit binary watermark found in Anthropic's Claude output, potentially tracking AI users

GlenBradley · x · 2026-08-11

X user Glen Bradley discovered a possible 26- or 28-bit binary number hidden in text generated by Anthropic's Claude, serving as an AI user-identifying fingerprint. The finding, based on a passage shared by Brian Roemmele, reveals subtle spacing and special characters that may encode a watermark, sparking discussions on traceability and privacy of AI-generated content.

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