KeyInfoEncryptedKey Class
Assembly: System.Security (in system.security.dll)
The KeyInfoEncryptedKey class wraps the EncryptedKey class, which allows you to add the EncryptedKey class as a subelement of the KeyInfo class. Initialize the KeyInfoEncryptedKey class to an instance of the EncryptedKey class when you need to add an encrypted session key to your encrypted XML document.
The following code example demonstrates how to encrypt an XML document using an asymmetric key. This example creates a symmetric session key to encrypt the document and then uses the asymmetric key to embed an encrypted version of the session key into the XML document.
Imports System Imports System.Xml Imports System.Security.Cryptography Imports System.Security.Cryptography.Xml Module Program Sub Main(ByVal args() As String) ' Create an XmlDocument object. Dim xmlDoc As New XmlDocument() ' Load an XML file into the XmlDocument object. Try xmlDoc.PreserveWhitespace = True xmlDoc.Load("test.xml") Catch e As Exception Console.WriteLine(e.Message) Return End Try ' Create a new RSA key. This key will encrypt a symmetric key, ' which will then be imbedded in the XML document. Dim rsaKey = New RSACryptoServiceProvider() Try ' Encrypt the "creditcard" element. Encrypt(xmlDoc, "creditcard", rsaKey, "rsaKey") ' Display the encrypted XML to the console. Console.WriteLine("Encrypted XML:") Console.WriteLine() Console.WriteLine(xmlDoc.OuterXml) ' Decrypt the "creditcard" element. Decrypt(xmlDoc, rsaKey, "rsaKey") ' Display the encrypted XML to the console. Console.WriteLine() Console.WriteLine("Decrypted XML:") Console.WriteLine() Console.WriteLine(xmlDoc.OuterXml) Catch e As Exception Console.WriteLine(e.Message) Finally ' Clear the RSA key. rsaKey.Clear() End Try End Sub Sub Encrypt(ByVal Doc As XmlDocument, ByVal ElementToEncrypt As String, ByVal Alg As RSA, ByVal KeyName As String) ' Check the arguments. If Doc Is Nothing Then Throw New ArgumentNullException("Doc") End If If ElementToEncrypt Is Nothing Then Throw New ArgumentNullException("ElementToEncrypt") End If If Alg Is Nothing Then Throw New ArgumentNullException("Alg") End If ''''''''''''''''''''''''''''''''''''''''''''''''''' ' Find the specified element in the XmlDocument ' object and create a new XmlElemnt object. ''''''''''''''''''''''''''''''''''''''''''''''''''' Dim elementEncrypt As XmlElement = Doc.GetElementsByTagName(ElementToEncrypt)(0) ' Throw an XmlException if the element was not found. If elementToEncrypt Is Nothing Then Throw New XmlException("The specified element was not found") End If ''''''''''''''''''''''''''''''''''''''''''''''''''' ' Create a new instance of the EncryptedXml class ' and use it to encrypt the XmlElement with the ' a new random symmetric key. ''''''''''''''''''''''''''''''''''''''''''''''''''' ' Create a 256 bit Rijndael key. Dim sessionKey As New RijndaelManaged() sessionKey.KeySize = 256 Dim eXml As New EncryptedXml() Dim encryptedElement As Byte() = eXml.EncryptData(elementEncrypt, sessionKey, False) ''''''''''''''''''''''''''''''''''''''''''''''''''' ' Construct an EncryptedData object and populate ' it with the desired encryption information. ''''''''''''''''''''''''''''''''''''''''''''''''''' Dim edElement As New EncryptedData() edElement.Type = EncryptedXml.XmlEncElementUrl ' Create an EncryptionMethod element so that the ' receiver knows which algorithm to use for decryption. edElement.EncryptionMethod = New EncryptionMethod(EncryptedXml.XmlEncAES256Url) ' Encrypt the session key and add it to an EncryptedKey element. Dim ek As New EncryptedKey() Dim encryptedKey As Byte() = EncryptedXml.EncryptKey(sessionKey.Key, Alg, False) ek.CipherData = New CipherData(encryptedKey) ek.EncryptionMethod = New EncryptionMethod(EncryptedXml.XmlEncRSA15Url) ' Set the KeyInfo element to specify the ' name of the RSA key. ' Create a new KeyInfo element. edElement.KeyInfo = New KeyInfo() ' Create a new KeyInfoName element. Dim kin As New KeyInfoName() ' Specify a name for the key. kin.Value = KeyName ' Add the KeyInfoName element to the ' EncryptedKey object. ek.KeyInfo.AddClause(kin) ' Add the encrypted key to the ' EncryptedData object. edElement.KeyInfo.AddClause(New KeyInfoEncryptedKey(ek)) ' Add the encrypted element data to the ' EncryptedData object. edElement.CipherData.CipherValue = encryptedElement ''''''''''''''''''''''''''''''''''''''''''''''''''' ' Replace the element from the original XmlDocument ' object with the EncryptedData element. ''''''''''''''''''''''''''''''''''''''''''''''''''' EncryptedXml.ReplaceElement(elementEncrypt, edElement, False) End Sub Sub Decrypt(ByVal Doc As XmlDocument, ByVal Alg As RSA, ByVal KeyName As String) ' Check the arguments. If Doc Is Nothing Then Throw New ArgumentNullException("Doc") End If If Alg Is Nothing Then Throw New ArgumentNullException("Alg") End If If KeyName Is Nothing Then Throw New ArgumentNullException("KeyName") End If ' Create a new EncryptedXml object. Dim exml As New EncryptedXml(Doc) ' Add a key-name mapping. ' This method can only decrypt documents ' that present the specified key name. exml.AddKeyNameMapping(KeyName, Alg) ' Decrypt the element. exml.DecryptDocument() End Sub End Module
import System.*;
import System.Xml.*;
import System.Security.Cryptography.*;
import System.Security.Cryptography.Xml.*;
class Program
{
public static void main(String[] args)
{
// Create an XmlDocument object.
XmlDocument xmlDoc = new XmlDocument();
// Load an XML file into the XmlDocument object.
try {
xmlDoc.set_PreserveWhitespace(true);
xmlDoc.Load("test.xml");
}
catch (System.Exception e) {
Console.WriteLine(e.get_Message());
return;
}
// Create a new RSA key. This key will encrypt a symmetric key,
// which will then be imbedded in the XML document.
RSA rsaKey = new RSACryptoServiceProvider();
try {
// Encrypt the "creditcard" element.
Encrypt(xmlDoc, "creditcard", rsaKey, "rsaKey");
// Display the encrypted XML to the console.
Console.WriteLine("Encrypted XML:");
Console.WriteLine();
Console.WriteLine(xmlDoc.get_OuterXml());
// Decrypt the "creditcard" element.
Decrypt(xmlDoc, rsaKey, "rsaKey");
// Display the encrypted XML to the console.
Console.WriteLine();
Console.WriteLine("Decrypted XML:");
Console.WriteLine();
Console.WriteLine(xmlDoc.get_OuterXml());
}
catch (System.Exception e) {
Console.WriteLine(e.get_Message());
}
finally {
// Clear the RSA key.
rsaKey.Clear();
}
} //main
public static void Encrypt(XmlDocument doc, String elementToEncrypt,
RSA alg, String keyName) throws ArgumentNullException,XmlException
{
// Check the arguments.
if (doc == null) {
throw new ArgumentNullException("doc");
}
if (elementToEncrypt == null) {
throw new ArgumentNullException("elementToEncrypt");
}
if (alg == null) {
throw new ArgumentNullException("alg");
}
////////////////////////////////////////////////
// Find the specified element in the XmlDocument
// object and create a new XmlElemnt object.
////////////////////////////////////////////////
XmlElement elementToEncrypt1 = (XmlElement)doc.GetElementsByTagName(
elementToEncrypt).get_ItemOf(0);
// Throw an XmlException if the element was not found.
if (elementToEncrypt1 == null) {
throw new XmlException("The specified element was not found");
}
//////////////////////////////////////////////////
// Create a new instance of the EncryptedXml class
// and use it to encrypt the XmlElement with the
// a new random symmetric key.
//////////////////////////////////////////////////
// Create a 256 bit Rijndael key.
RijndaelManaged sessionKey = new RijndaelManaged();
sessionKey.set_KeySize(256);
EncryptedXml eXml = new EncryptedXml();
ubyte encryptedElement[] = eXml.EncryptData(elementToEncrypt1,
sessionKey, false);
////////////////////////////////////////////////
// Construct an EncryptedData object and populate
// it with the desired encryption information.
////////////////////////////////////////////////
EncryptedData edElement = new EncryptedData();
edElement.set_Type(EncryptedXml.XmlEncElementUrl);
// Create an EncryptionMethod element so that the
// receiver knows which algorithm to use for decryption.
edElement.set_EncryptionMethod(new EncryptionMethod(
EncryptedXml.XmlEncAES256Url));
// Encrypt the session key and add it to an EncryptedKey element.
EncryptedKey ek = new EncryptedKey();
ubyte encryptedKey[] = EncryptedXml.EncryptKey(sessionKey.get_Key(),
alg, false);
ek.set_CipherData(new CipherData(encryptedKey));
ek.set_EncryptionMethod(new EncryptionMethod(EncryptedXml.
XmlEncRSA15Url));
// Set the KeyInfo element to specify the
// name of the RSA key.
// Create a new KeyInfo element.
edElement.set_KeyInfo(new KeyInfo());
// Create a new KeyInfoName element.
KeyInfoName kin = new KeyInfoName();
// Specify a name for the key.
kin.set_Value(keyName);
// Add the KeyInfoName element to the
// EncryptedKey object.
ek.get_KeyInfo().AddClause(kin);
// Add the encrypted key to the
// EncryptedData object.
edElement.get_KeyInfo().AddClause(new KeyInfoEncryptedKey(ek));
// Add the encrypted element data to the
// EncryptedData object.
edElement.get_CipherData().set_CipherValue(encryptedElement);
////////////////////////////////////////////////////
// Replace the element from the original XmlDocument
// object with the EncryptedData element.
////////////////////////////////////////////////////
EncryptedXml.ReplaceElement(elementToEncrypt1, edElement, false);
} //Encrypt
public static void Decrypt(XmlDocument doc, RSA alg, String keyName)
{
// Check the arguments.
if (doc == null) {
throw new ArgumentNullException("doc");
}
if (alg == null) {
throw new ArgumentNullException("alg");
}
if (keyName == null) {
throw new ArgumentNullException("keyName");
}
// Create a new EncryptedXml object.
EncryptedXml eXml = new EncryptedXml(doc);
// Add a key-name mapping.
// This method can only decrypt documents
// that present the specified key name.
eXml.AddKeyNameMapping(keyName, alg);
// Decrypt the element.
eXml.DecryptDocument();
} //Decrypt
} //Program
System.Security.Cryptography.Xml.KeyInfoClause
System.Security.Cryptography.Xml.KeyInfoEncryptedKey
Windows 98, Windows Server 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.