identity/com.midnight.kuira.core.identity.backup/SeedDeriver/deriveBip39Seed

deriveBip39Seed

suspend fun deriveBip39Seed(activity: Activity, passkeyManager: PasskeyManager): ByteArray

One-shot: passkey PRF → BIP-39 entropy → mnemonic → BIP-39 seed.

The returned 64-byte seed is what MidnightSdk.Builder.seed(...) consumes. Identical on every device + every Kuira ecosystem app that shares the RP, because PRF is deterministic in (passkey, salt) and the entropy → seed chain is purely deterministic.

Caller MUST wipe the returned ByteArray once the SDK has copied it — same contract as PlaintextSeed.bip39Seed.