Encryption in Windows 98

[grip003]

I wrote a simple encryption class to handle encrypting strings and byte arrays. Everything works perfectly in Windows XP and Windows 2000, but I get the following error in Windows 98:

 

Byte array is too large. The maximum size byte array that can be encrypted by this public key implementation is 16 bytes.

 

I am getting this error in the following code

public static byte[] RSAEncrypt(byte[] DataToEncrypt,
string key_file)
{
// Encryption is done using the public key.
try
{
	System.Windows.Forms.MessageBox.Show("Creating " +
		"RSACryptoServiceProvider.");
	// Create a new instance of RSACryptoServiceProvider
	RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();

	// Import the RSA Key information, which only needs to
	//  include the public key information.
	System.IO.FileStream reader = new System.IO.FileStream(
		key_file, System.IO.FileMode.Open, System.IO.FileAccess.Read);
	System.Xml.XmlTextReader xml_reader =
		new System.Xml.XmlTextReader(reader);
	System.Xml.XmlDocument doc = new System.Xml.XmlDocument();
	doc.Load(xml_reader);
	xml_reader.Close();
	reader.Close();
		
	RSA.FromXmlString(doc.InnerXml);
			
	// By default this will create a 128 bit AES object
	SymmetricAlgorithm sa = SymmetricAlgorithm.Create();
	ICryptoTransform ct = sa.CreateEncryptor();
	byte[] encrypt = ct.TransformFinalBlock(
		DataToEncrypt, 0, DataToEncrypt.Length);

	RSAPKCS1KeyExchangeFormatter fmt = new RSAPKCS1KeyExchangeFormatter(RSA);
	byte[] keyex = fmt.CreateKeyExchange(sa.Key);

	// return the key exchange, the IV (public) and encrypted data
	byte[] result = new byte [keyex.Length + sa.IV.Length + encrypt.Length];
	Buffer.BlockCopy(keyex, 0, result, 0, keyex.Length);
	Buffer.BlockCopy(sa.IV, 0, result, keyex.Length, sa.IV.Length);
	Buffer.BlockCopy(encrypt, 0, result, keyex.Length + sa.IV.Length,
		encrypt.Length);
	return result;
}
catch (Exception ex)
{
	System.Windows.Forms.MessageBox.Show("Exception!!\n" +
		ex.Message);
	return null;
}
}// end RSAEncrypt(byte[] DataToEncrypt, string key_file)

 

The error comes on line byte[] keyex = fmt.CreateKeyExchange(sa.Key);

I have I.E. 6.0 installed on the 98 machine, which should include the strong encryption that I need, at least that's what I've heard. Can anyone help me out here?