/// <summary>
/// Revert the obfuscated XML document of <paramref name="value"/> to its original state by applying the mappable XML document of <paramref name="mapping"/>.
/// </summary>
/// <param name="value">The obfuscated <see cref="Stream"/> to revert.</param>
/// <param name="mapping">A <see cref="Stream"/> containing mappable values necessary to revert <paramref name="value"/> to its original state.</param>
/// <returns>
/// A <see cref="Stream"/> object where the obfuscated XML document has been reverted to its original XML document.
/// </returns>
public override Stream Revert(Stream value, Stream mapping)
{
if (value == null)
{
throw new ArgumentNullException(nameof(value));
}
if (mapping == null)
{
throw new ArgumentNullException(nameof(mapping));
}
MemoryStream tempOutput = null;
try
{
XmlDocument document = XmlDocumentConverter.FromStream(mapping);
var mappingNode = document.DocumentElement;
XmlNode encryptedNode = mappingNode.GetElementsByTagName(MappingEncryptedElement).Item(0);
if (encryptedNode != null)
{
mappingNode.InnerXml = StringConverter.FromBytes(AdvancedEncryptionStandardUtility.Decrypt(Convert.FromBase64String(encryptedNode.InnerText), Key, InitializationVector), options =>
{
options.Encoding = Encoding;
options.Preamble = PreambleSequence.Remove;
});
}
tempOutput = new MemoryStream();
using (XmlWriter writer = XmlWriter.Create(tempOutput, XmlWriterUtility.CreateSettings(o => o.Encoding = Encoding)))
{
document.WriteTo(writer);
}
tempOutput.Position = 0;
mapping = tempOutput;
tempOutput = null;
}
finally
{
if (tempOutput != null)
{
tempOutput.Dispose();
}
}
return(base.Revert(value, mapping));
}
/// <summary>
/// Creates and returns a mappable XML document of the original values and the obfuscated values.
/// </summary>
/// <returns>A mappable XML document of the original values and the obfuscated values.</returns>
public override Stream CreateMapping()
{
MemoryStream output;
MemoryStream tempOutput = null;
try
{
XmlDocument document = XmlDocumentConverter.FromStream(base.CreateMapping());
XmlNode mappingNode = document.DocumentElement;
string innerXmlOfMappingNode = mappingNode.InnerXml;
byte[] innerXmlOfMappingNodeBytes = ByteConverter.FromString(innerXmlOfMappingNode, options =>
{
options.Encoding = Encoding;
options.Preamble = PreambleSequence.Remove;
});
XmlElement encryptedNode = document.CreateElement(MappingEncryptedElement);
encryptedNode.InnerText = Convert.ToBase64String(AdvancedEncryptionStandardUtility.Encrypt(innerXmlOfMappingNodeBytes, Key, InitializationVector));
mappingNode.InnerXml = "";
mappingNode.AppendChild(encryptedNode);
tempOutput = new MemoryStream();
using (XmlWriter writer = XmlWriter.Create(tempOutput, XmlWriterUtility.CreateSettings(o => o.Encoding = Encoding)))
{
document.WriteTo(writer);
}
tempOutput.Position = 0;
output = tempOutput;
tempOutput = null;
}
finally
{
if (tempOutput != null)
{
tempOutput.Dispose();
}
}
return(output);
}
