public static byte[] EncryptOuterContainer(OuterContainer outerContainer, InnerContainer innerContainer, byte[] key)
{
XmlDocument outerContainerXml = SerializeOuterContainer(outerContainer);
XmlDocument innerContainerXml = SerializeInnerContainer(innerContainer);
XmlElement encryptedDataPlaceholder = outerContainerXml.GetElementsByTagName("EncryptedDataPlaceholder")[0] as XmlElement;
XmlElement plaintextInnerContainer = innerContainerXml.GetElementsByTagName("InnerContainer")[0] as XmlElement;
EncryptedData encryptedData = new EncryptedData();
encryptedData.Type = EncryptedXml.XmlEncElementUrl;
encryptedData.EncryptionMethod = new EncryptionMethod(EncryptedXml.XmlEncAES256Url);
EncryptedXml encryptedXml = new EncryptedXml();
using (AesCryptoServiceProvider aesCsp = new AesCryptoServiceProvider())
{
aesCsp.KeySize = 256; // critical security parameter
aesCsp.Key = key; // critical security parameter
aesCsp.Mode = CipherMode.CBC; // critical security parameter
aesCsp.GenerateIV(); // critical security parameter
encryptedData.CipherData.CipherValue = encryptedXml.EncryptData(plaintextInnerContainer, aesCsp, false);
}
EncryptedXml.ReplaceElement(encryptedDataPlaceholder, encryptedData, false);
byte[] outerContainerBytes = Encoding.UTF8.GetBytes(outerContainerXml.OuterXml);
byte[] fileBytes = Shared.Utility.Compress(outerContainerBytes);
return(fileBytes);
}
public static InnerContainer CreateInnerContainer()
{
InnerContainer innerContainer = new InnerContainer();
innerContainer.Version = "1.0";
innerContainer.Keys = new ObservableCollection <KeyItem>();
innerContainer.NextKeyNumber = 1;
innerContainer.Groups = new ObservableCollection <GroupItem>();
innerContainer.NextGroupNumber = 1;
return(innerContainer);
}
public static XmlDocument SerializeInnerContainer(InnerContainer innerContainer)
{
XmlDocument doc = new XmlDocument();
XmlDeclaration xmlDeclaration = doc.CreateXmlDeclaration("1.0", "UTF-8", null);
doc.InsertBefore(xmlDeclaration, doc.DocumentElement);
XPathNavigator nav = doc.CreateNavigator();
using (XmlWriter w = nav.AppendChild())
{
XmlSerializerNamespaces ns = new XmlSerializerNamespaces();
ns.Add(string.Empty, string.Empty); // remove xsd and xsi attributes
XmlSerializer s = new XmlSerializer(typeof(InnerContainer));
s.Serialize(w, innerContainer, ns);
}
return(doc);
}
