QIF-T0100

Neural steganographic encoding (inaudible audio watermarking for covert neural command/biofingerprint channel)

Embedding data in audio signals below the human hearing threshold (>18 kHz ultrasonic or <20 Hz infrasonic) or within psychoacoustic masking bands of audible content. The encoded signal is imperceptible to the listener but decodable by a receiver with knowledge of the encoding scheme. In the adversarial case, the hidden channel carries covert commands, tracking identifiers, or subliminal cues targeting auditory processing pathways (e.g., triggering pre-conditioned responses or influencing decision-making). In the protective case, the same physics enables steganographic embedding of neural biofingerprints for authentication — the signal evokes a measurable auditory evoked potential (AEP) unique to the individual's cochlear geometry and auditory cortex response, functioning as a biometric watermark. Initial enrollment/profiling phase required to capture individual's unique AEP response. Practical constraints include target device's ability to accurately reproduce encoded frequencies and effective transmission range (1-10m). Psychoacoustic masking threshold follows: T_mask(f) = L_masker - (sf × |f - f_masker|) where sf is the spreading factor (~25 dB/Bark on upper slope, ~10 dB/Bark on lower slope). Auditory steady-state response (ASSR) at 40 Hz provides the mechanism for neural biofingerprint verification. Proves TARA's cross-domain dual-use thesis: same physics operates as attack vector, defense mechanism, and therapeutic tool.