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KeyInfoEncryptedKey Class

Note: This class is new in the .NET Framework version 2.0.

Wraps the EncryptedKey class, it to be placed as a subelement of the KeyInfo class.

Namespace: System.Security.Cryptography.Xml
Assembly: System.Security (in system.security.dll)

public class KeyInfoEncryptedKey : KeyInfoClause
public class KeyInfoEncryptedKey extends KeyInfoClause
public class KeyInfoEncryptedKey extends KeyInfoClause

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.

using System;
using System.Xml;
using System.Security.Cryptography;
using System.Security.Cryptography.Xml;

class Program
{
    static void Main(string[] args)
    {

        // Create an XmlDocument object.
        XmlDocument xmlDoc = new XmlDocument();

        // Load an XML file into the XmlDocument object.
        try
        {
            xmlDoc.PreserveWhitespace = true;
            xmlDoc.Load("test.xml");
        }
        catch (Exception e)
        {
            Console.WriteLine(e.Message);
        }

        // 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.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 (Exception e)
        {
            Console.WriteLine(e.Message);
        }
        finally
        {
            // Clear the RSA key.
            rsaKey.Clear();
        }

    }

    public static void Encrypt(XmlDocument Doc, string ElementToEncrypt, RSA Alg, string KeyName)
    {
        // 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 elementToEncrypt = Doc.GetElementsByTagName(ElementToEncrypt)[0] as XmlElement;

        // Throw an XmlException if the element was not found.
        if (elementToEncrypt == 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.KeySize = 256;

        EncryptedXml eXml = new EncryptedXml();

        byte[] encryptedElement = eXml.EncryptData(elementToEncrypt, sessionKey, false);

        ////////////////////////////////////////////////
        // Construct an EncryptedData object and populate
        // it with the desired encryption information.
        ////////////////////////////////////////////////


        EncryptedData edElement = 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.
        EncryptedKey ek = new EncryptedKey();

        byte[] encryptedKey = 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.
        KeyInfoName kin = 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(elementToEncrypt, edElement, false);

    }

    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();

    }

}

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());
        }
        // 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.Object
   System.Security.Cryptography.Xml.KeyInfoClause
    System.Security.Cryptography.Xml.KeyInfoEncryptedKey

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 98, Windows 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 .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0

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