EncryptionPropertyCollection Class


Represents a collection of EncryptionProperty classes 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 EncryptionPropertyCollection : IList, ICollection, 


Initializes a new instance of the EncryptionPropertyCollection class.


Gets the number of elements contained in the EncryptionPropertyCollection object.


Gets a value that indicates whether the EncryptionPropertyCollection object has a fixed size.


Gets a value that indicates whether the EncryptionPropertyCollection object is read-only.


Gets a value that indicates whether access to the EncryptionPropertyCollection object is synchronized (thread safe).


Gets or sets the EncryptionProperty object at the specified index.


Gets an object that can be used to synchronize access to the EncryptionPropertyCollection object.


Adds an EncryptionProperty object to the EncryptionPropertyCollection object.


Removes all items from the EncryptionPropertyCollection object.


Determines whether the EncryptionPropertyCollection object contains a specific EncryptionProperty object.

System_CAPS_pubmethodCopyTo(Array, Int32)

Copies the elements of the EncryptionPropertyCollection object to an array, starting at a particular array index.

System_CAPS_pubmethodCopyTo(EncryptionProperty[], Int32)

Copies the elements of the EncryptionPropertyCollection object to an array of EncryptionProperty objects, starting at a particular array index.


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


Returns an enumerator that iterates through an EncryptionPropertyCollection object.


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


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


Determines the index of a specific item in the EncryptionPropertyCollection object.

System_CAPS_pubmethodInsert(Int32, EncryptionProperty)

Inserts an EncryptionProperty object into the EncryptionPropertyCollection object at the specified position.


Returns the EncryptionProperty object at the specified index.


Removes the first occurrence of a specific EncryptionProperty object from the EncryptionPropertyCollection object.


Removes the EncryptionProperty object at the specified index.


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


Adds an item to the IList.


Determines whether the IList contains a specific value.


Determines the index of a specific item in the IList.

System_CAPS_pubinterfaceSystem_CAPS_privmethodIList.Insert(Int32, Object)

Inserts an item to the IList at the specified index.


Removes the first occurrence of a specific object from the IList.


Gets the element at the specified index.


Overloaded. Enables parallelization of a query.(Defined by ParallelEnumerable.)


Overloaded. Converts an IEnumerable to an IQueryable.(Defined by Queryable.)


Casts the elements of an IEnumerable to the specified type.(Defined by Enumerable.)


Filters the elements of an IEnumerable based on a specified type.(Defined by Enumerable.)

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, you can 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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