C#

public static object ConvertObject(object source, Type targetType)
{
    object result;
    Type sourceType = source.GetType();

    DataContractSerializer sourceSerializer = new DataContractSerializer(sourceType);

    using (MemoryStream ms = new MemoryStream())
    {
        DateTime start = DateTime.Now;
        sourceSerializer.WriteObject(ms, source);
        TimeSpan writeObjectTime = DateTime.Now - start;

        ms.Seek(0, SeekOrigin.Begin);

        DataContractSerializer targetSerializer = new DataContractSerializer(targetType);
        XmlReader r = XmlReader.Create(ms);

        DynamicObjectSerializer.MyReader myreader = new DynamicObjectSerializer.MyReader(r);

        start = DateTime.Now;
        result = targetSerializer.ReadObject(myreader);
        TimeSpan readObjectTime = DateTime.Now - start;

        LoggerHolder.LogDebug("\"{0}\" Write Time = {1}, Read Time = {2}", source.GetType().Name, writeObjectTime, readObjectTime);
    }
    return result;
}

public static bool CheckSignature(string key64, string sig64)
      {
          var key = Convert.FromBase64String(key64);
          var sig = Convert.FromBase64String(sig64);

          var rsa = new RSACryptoServiceProvider(new CspParameters
          {
              Flags = CspProviderFlags.UseMachineKeyStore
          });
          rsa.FromXmlString("<RSAKeyValue><Modulus>4IlzOY3Y9fXoh3Y5f06wBbtTg94Pt6vcfcd1KQ0FLm0S36aGJtTSb6pYKfyX7PqCUQ8wgL6xUJ5GRPEsu9 gyz8ZobwfZsGCsvu40CWoT9fcFBZPfXro1Vtlh/xl/yYHm+Gzqh0Bw76xtLHSfLfpVOrmZdwKmSFKMTvNXOFd0V18=</Modulus><Exponent>AQAB</Exponent></RSAKeyValue>");
          var def = new RSAPKCS1SignatureDeformatter();
          def.SetKey(rsa);
          def.SetHashAlgorithm("MD5");

          return def.VerifySignature(key, sig);

      }

public static byte[] CreateSignature(string key64)
 {
     var data = Convert.FromBase64String(key64);

     var rSaCryptoServiceProvider = new RSACryptoServiceProvider(new CspParameters
     {
        Flags = CspProviderFlags.UseMachineKeyStore
     });

     rSaCryptoServiceProvider.FromXmlString("<RSAKeyValue><Modulus>4IlzOY3Y9fXoh3Y5f06wBbtTg94Pt6vcfcd1KQ0FLm0S36aGJtTSb6pYKfyX7PqCUQ8wgL6xUJ5GRPEsu9 gyz8ZobwfZsGCsvu40CWoT9fcFBZPfXro1Vtlh/xl/yYHm+Gzqh0Bw76xtLHSfLfpVOrmZdwKmSFKMTvNXOFd0V18=</Modulus><Exponent>AQAB</Exponent></RSAKeyValue>");


     var RSAform = new RSAPKCS1SignatureFormatter();
     RSAform.SetKey(rSaCryptoServiceProvider);
     RSAform.SetHashAlgorithm("MD5");

     byte[] hashData = CalculateMD5Hash(data);

     return RSAform.CreateSignature(hashData);
 }