csharp md5

                
                        private static string CalculateMd5(string filePathName) {
   using (var stream = File.OpenRead(filePathName))
   using (var md5 = MD5.Create()) {
      var hash = md5.ComputeHash(stream);
      var base64String = Convert.ToBase64String(hash);
      return base64String;
   }
}