Claude Code silently fingerprints users with steganographic markers
Claude Code silently fingerprints users with steganographic markers A developer reverse-engineering the Claude Code binary has discovered that Anthropic's command-line coding tool embeds hidden classification signals into system prompts before sending them to the API. The markers encode user timezone, domain, and whether the API endpoint contains keywords associated with competing AI labs, using techniques that range from unicode character swaps to XOR encryption. The findings were published
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