Hello developers and apple support team. Im was quite surprised why it's not possible to get SecKey reference for key which was generated using DCAppAttestService.generateKey() Case 1. So after self.iosDeviceAttestationManager.generateKey { keyId, error in guard let keyId = keyId else { promise(.failure(error!)) return } promise(.success(keyId)) } Then Im converting keyId from string to Data using guard let keyIdData = Data(base64Encoded: keyId) else { return Fail(error: Errors.someError).eraseToAnyPublisher() } P.S. Actually I have tried convert keyId as pure string to data but it also does not work let keyIdData = keyID.data(using: .utf8)! Then Im trying to obtain this key using standard keychain API. let getquery: [String: Any] = [ kSecClass as String: kSecClassKey, kSecAttrApplicationTag as String: keyIdData, kSecAttrKeyType as String: kSecAttrKeyTypeECSECPrimeRandom, kSecReturnRef as String: true] var item: CFTypeRef? let status = SecItemCopyMatching(getquery as CFDictionary, &item) guard status == errSecSuccess else { print("SecItemCopyMatching failed. Status = \(status)") return nil } Which return me SecItemCopyMatching failed. Status = -25300 Which means that itemNot found in keychain. Why it's happening? Case 2. I have tried other way around to create ECKey using let access = SecAccessControlCreateWithFlags( kCFAllocatorDefault, kSecAttrAccessibleWhenUnlockedThisDeviceOnly, .privateKeyUsage, nil) let ECKeySize = 256 let attributes: NSDictionary = [ kSecAttrKeyType: kSecAttrKeyTypeECSECPrimeRandom, kSecAttrKeySizeInBits: ECKeySize, kSecAttrTokenID: kSecAttrTokenIDSecureEnclave, kSecPrivateKeyAttrs: [ kSecAttrIsPermanent: true, kSecAttrApplicationTag: keyTagData, kSecAttrAccessControl: access as Any ] ] var error: Unmanaged<CFError>? guard let privateKey = SecKeyCreateRandomKey(attributes as CFDictionary, &error) else { error!.takeRetainedValue() as Error return nil } and then trying to attest this key using self.iosDeviceAttestationManager.attestKey(keyId, clientDataHash: clientDataHash) { data, error in guard let data = data else { promise(.failure(error!)) return } promise(.success(data)) } But this gives me error Error Domain=com.apple.devicecheck.error Code=3 "(null)" Which states fot InvalidKey So is there any way how I could get reference to attested key to later use it for signing/verification purposes? Thanks, in advance!