var Token= BuildAuthAsync("GET", body, URL);protected string BuildAuthAsync(string method, string body, string uri){var timestamp = DateTimeOffset.Now.ToUnixTimeSeconds();string nonce = Path.GetRandomFileName();string message = $"{method}\n{uri}\n{timestamp}\n{nonce}\n{body}\n";string signature = RequestSign(message);times = timestamp.ToString();noncerodom = nonce;sign = signature;return $"mchid=\"{mchid}\",nonce_str=\"{nonce}\",timestamp=\"{timestamp}\",serial_no=\"{serial_no}\",signature=\"{signature}\"";}protected string RequestSign(string message){X509Certificate2 cer = new X509Certificate2("../../File/1628286360_20231122_cert/apiclient_cert.p12", mchid, X509KeyStorageFlags.Exportable);if (cer != null){RSA rsa = cer.GetRSAPrivateKey();byte[] data = Encoding.UTF8.GetBytes(message);return Convert.ToBase64String(rsa.SignData(data, HashAlgorithmName.SHA256, RSASignaturePadding.Pkcs1));}else{return "";}}