This document explains how Kohaku derives private note secrets from a seed phrase using deterministic signatures. It is for wallet implementers who need to reproduce those notes, integrate a hardware wallet, or recover an existing wallet. It includes exact encodings, test vectors, and a runnable verifier.
Hardware wallets generally cannot run the required zero-knowledge prover, so the host needs the note secrets to create proofs. A compatible hardware wallet can produce a deterministic signature without exporting its seed or account private key. The host derives the note secrets from that signature and proves off-device. The exported signature is therefore sensitive note material, while the account private key stays on the device.