EncryptionProperty Class


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Represents the <EncryptionProperty> element used in XML encryption. This class cannot be inherited.

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


[HostProtectionAttribute(SecurityAction.LinkDemand, MayLeakOnAbort = true)]
public sealed class EncryptionProperty


Initializes a new instance of the EncryptionProperty class.


Initializes a new instance of the EncryptionProperty class using an XmlElement object.


Gets the ID of the current EncryptionProperty object.


Gets or sets an XmlElement object that represents an EncryptionProperty object.


Gets the target of the EncryptionProperty object.


Determines whether the specified object is equal to the current object.(Inherited from Object.)


Serves as the default hash function. (Inherited from Object.)


Gets the Type of the current instance.(Inherited from Object.)


Returns an XmlElement object that encapsulates an instance of the EncryptionProperty class.


Parses the input XmlElement and configures the internal state of the EncryptionProperty object to match.


Returns a string that represents the current object.(Inherited from Object.)

The EncryptionProperty class encapsulates the <EncryptionProperty> element defined by the World Wide Web Consortium XML Encryption specification located at http://www.w3.org/TR/xmlenc-core/.

Use the EncryptionProperty class to provide additional encryption information related to the EncryptedData and EncryptedKey elements. For example, use this class to specify a time stamp.

The following code example encrypts and decrypts an XML document. This code example creates an EncryptionProperty object that contains custom information about the EncryptedKey element, and adds the EncryptionProperty object to the EncryptionPropertyCollection collection of the EncryptedXml class. Finally, this code example displays information about the EncryptionProperty object and the EncryptionPropertyCollection collection.

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.
            xmlDoc.PreserveWhitespace = true;
        catch (Exception e)

        // 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();

            // Encrypt the "creditcard" element.
            Encrypt(xmlDoc, "creditcard", rsaKey, "rsaKey");

            // Inspect the EncryptedKey element.

            // Decrypt the "creditcard" element.
            Decrypt(xmlDoc, rsaKey, "rsaKey");

        catch (Exception e)
            // Clear the RSA key.


    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);

        // Save some more information about the key using
        // the EncryptionProperty element.  In this example,
        // we will save the value "LibVersion1".  You can save
        // anything you want here.

        // Create a new "EncryptionProperty" XmlElement object. 
        XmlElement element =  new XmlDocument().CreateElement("EncryptionProperty", EncryptedXml.XmlEncNamespaceUrl);

        // Set the value of the EncryptionProperty" XmlElement object.
        element.InnerText = "LibVersion1";

        // Create the EncryptionProperty object using the XmlElement object. 
        EncryptionProperty encProp = new EncryptionProperty(element);

        // Add the EncryptionProperty object to the EncryptedData object.

        // 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.

        // 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.


    static void InspectElement(XmlDocument Doc)
        // Get the EncryptedData element from the XMLDocument object.
        XmlElement encryptedData = Doc.GetElementsByTagName("EncryptedData")[0] as XmlElement;

        // Create a new EncryptedData object.
        EncryptedData encData = new EncryptedData();

        // Load the XML from the document to
        // initialize the EncryptedData object.

        // Display the properties.
        // Most values are Null by default.

        Console.WriteLine("EncryptedData.CipherData: " + encData.CipherData.GetXml().InnerXml);
        Console.WriteLine("EncryptedData.Encoding: " + encData.Encoding);
        Console.WriteLine("EncryptedData.EncryptionMethod: " + encData.EncryptionMethod.GetXml().InnerXml);

        EncryptionPropertyCollection encPropCollection = encData.EncryptionProperties;

        Console.WriteLine("Number of elements in the EncryptionPropertyCollection: " + encPropCollection.Count);

        foreach(EncryptionProperty encProp in encPropCollection)
                Console.WriteLine("EncryptionProperty.ID: " + encProp.Id);
                Console.WriteLine("EncryptionProperty.PropertyElement: " + encProp.PropertyElement.InnerXml);
                Console.WriteLine("EncryptionProperty.Target: " + encProp.Target);


        Console.WriteLine("EncryptedData.Id: " + encData.Id);
        Console.WriteLine("EncryptedData.KeyInfo: " + encData.KeyInfo.GetXml().InnerXml);
        Console.WriteLine("EncryptedData.MimeType: " + encData.MimeType);


.NET Framework
Available since 2.0

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

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