//This method creates the public, private and secret (symmetric) keys and saves them to XML files to be used later.
static void initialize()
{
//Generate a public/private key pair.
RSACryptoServiceProvider SenderKeys = new RSACryptoServiceProvider();
//Generate a second public/private key pair.
RSACryptoServiceProvider ReceiverKeys = new RSACryptoServiceProvider();
//Generate a symmetric binary key
RijndaelManaged SymmetricKey = new RijndaelManaged();
SymmetricKey.KeySize = 128;
SymmetricKey.BlockSize = 128;
SymmetricKey.Mode = CipherMode.CBC;
//Convert the keys into xml strings
String SenderKeyXML = RSACryptoServiceProviderExtensions.ToXmlString(SenderKeys);
String ReceiverKeyXML = RSACryptoServiceProviderExtensions.ToXmlString(ReceiverKeys);
String SymmetricKeyXML = "<root><mykey>'" + Convert.ToBase64String(SymmetricKey.Key) + "'</mykey><IV>'" +
Convert.ToBase64String(SymmetricKey.IV) + "'</IV></root>";
//Save the xml strings to respective files
XmlDocument xmlDoc = new XmlDocument();
xmlDoc.LoadXml(SenderKeyXML);
xmlDoc.Save("SenderKeys.xml");
xmlDoc.LoadXml(ReceiverKeyXML);
xmlDoc.Save("ReceiverKeys.xml");
xmlDoc.LoadXml(SymmetricKeyXML);
xmlDoc.Save("SymmetricKey.xml");
}
//This method loads the stored keys from the xml where they are saved
static void loadKeys(RSACryptoServiceProvider SenderKeys, RSACryptoServiceProvider ReceiverKeys, RijndaelManaged SymmetricKey)
{
//Load all the keys
XmlDocument xmlDoc = new XmlDocument();
//Sender keys
xmlDoc.Load("SenderKeys.xml");
String SenderKeysXML = xmlDoc.OuterXml;
RSACryptoServiceProviderExtensions.FromXmlString(SenderKeys, SenderKeysXML);
//Receiver keys
xmlDoc.Load("ReceiverKeys.xml");
String ReceiverKeysXML = xmlDoc.OuterXml;
RSACryptoServiceProviderExtensions.FromXmlString(ReceiverKeys, ReceiverKeysXML);
//Symmetric key
xmlDoc.Load("SymmetricKey.xml");
string keyString = xmlDoc.FirstChild.FirstChild.InnerText;
string ivString = xmlDoc.FirstChild.LastChild.InnerText;
SymmetricKey.KeySize = 128;
SymmetricKey.BlockSize = 128;
SymmetricKey.Mode = CipherMode.CBC;
SymmetricKey.Key = Convert.FromBase64String(keyString.Substring(1, keyString.Length - 2));
SymmetricKey.IV = Convert.FromBase64String(ivString.Substring(1, keyString.Length - 2));
}
