Thanks Eskimo, I found the problem. The behaveour in xCode and in TestFlight is diferent.

I extend this post with the method that I override of the webview, and that is missing in the previous code: func webView(_ webView: WKWebView, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {    let method = challenge.protectionSpace.authenticationMethod    switch method {    case NSURLAuthenticationMethodClientCertificate:        sendClientCertificate(for: challenge, via: completionHandler)    default:     completionHandler(.performDefaultHandling, .none)    }   }

In case it helps anyone else, with CryptoSwift you can create an RSA key by passing these parameters and it is possible to decrypt the encrypted message with your public key.

This master tables are resdonly, but other tables in the database are writable by the app.

It could be an option. I did not know that an sqlite file could be sent. How could it be done?