watermark::Key

Cryptographic key for watermark embedding and detection.

Detailed description

Manages the secret key material backing the spread-spectrum watermarking pipeline. Derives from either a passphrase (SHA-256 stretched) or raw bytes; once constructed it exposes three deterministic-PRNG helpers — generateSpreadSequence (±1 chip sequence for direct-sequence spread spectrum), generateFloatSequence (uniform [0,1) floats), and generatePermutation (index reshuffle for picking which triangles / vertices carry payload). keyedHash provides a 32-byte fingerprint primitive for integrity paths.

See also watermark::Watermarker.