# privateKey Base64-encoded ED25519-V3 private key, or `nil` if discarded. ``` let privateKey: String? ``` ## Discussion Populated when `ADD_ONION` was called **without** `DiscardPK`. Persist in a secure store to later re-adopt the service via [`OnionKeySpec.providedV3(_:)`](/documentation/Tor/OnionKeySpec/providedV3(_:)). `nil` indicates the key was generated with `discardPrivateKey: true` and cannot be recovered. > Important: Secret material — see the type-level `Important` > note on storage.