Bit-exact lossless audio encryption for irreplaceable intangible cultural heritage using chaotic-lifting fourier transform

Digital audio archives of intangible cultural heritage (ICH) face risks of unauthorized replication, covert tampering, and silent data corruption that cannot be fully mitigated through policy-based governance alone. Archival preservation of 48 kHz/24-bit stereo WAV recordings requires simultaneous guarantees of confidentiality, bit-exact recoverability, and verifiable integrity. This study introduces a bit-exact lossless audio encryption scheme that operates entirely in the integer domain and is based on the chaotic-lifting Fourier transform, combined with key-dependent permutation, diffusion, and ciphertext-feedback whitening. Bit-exact reconstruction is verified at both frame and full-signal levels. Ciphertext exhibits near-ideal statistical properties, with entropy approaching 8 bits and negligible correlation. The method shows strong sensitivity to 1-bit perturbations and incorporates frame-level HMAC-SHA256 authentication achieving 100% tamper detection. These results establish a practical cryptographic preservation approach enabling reproducible storage and controlled access for irreplaceable ICH audio archives.