Poisoned Identifiers Survive LLM Deobfuscation: A Case Study on Claude Opus 4.6

Research study reveals that when Claude Opus 4.6 deobfuscates JavaScript code, poisoned identifier names from the original string table consistently survive in the reconstructed code, even when the AI demonstrates correct understanding of the code's semantics. Changing the task framing from 'deobfuscate' to 'write fresh implementation' significantly reduced this persistence while maintaining algorithmic accuracy.