P256K P256K P256K.MuSig P256K.MuSig.NonceResult secnonce Instance Property secnonce The secret nonce to pass exactly once to partialSignature(for:pubnonce:secureNonce:publicNonceAggregate:xonlyKeyAggregate:). iOS 13.0+ macCatalyst 13.0+ macOS 10.15+ tvOS 13.0+ visionOS 1.0+ watchOS 6.0+ let secnonce: P256K.Schnorr.SecureNonce