EncryptedKey Class

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

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

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

Public NotInheritable Class EncryptedKey
	Inherits EncryptedType
Dim instance As EncryptedKey

public final class EncryptedKey extends EncryptedType
public final class EncryptedKey extends EncryptedType

This class represents the <EncryptedKey> element in XML encryption. The <EncryptedKey> element is used to send encryption keys. It can be created in a stand-alone XML document, be placed within an application document, or be inside an <EncryptedData> element as a child of a <KeyInfo> element. The key value is always encrypted to the recipient. When <EncryptedKey> is decrypted, the resulting key is made available to the <EncryptionMethod> algorithm without any additional processing.

The <EncryptedKey> element is similar to the <EncryptedData> element of the EncryptedData class except that the data encrypted is always a key value.

The following code example illustrates how to encrypt and decrypt an XML element using the EncryptedKey class. This example then displays the values of various properties of the EncryptedKey class to the console.

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.
            xmlDoc.PreserveWhitespace = True
        Catch e As Exception
        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 As New RSACryptoServiceProvider()

            ' Encrypt the "creditcard" element.
            Encrypt(xmlDoc, "creditcard", rsaKey, "rsaKey")

            ' Inspect the EncryptedKey element.

            ' Decrypt the "creditcard" element.
            Decrypt(xmlDoc, rsaKey, "rsaKey")

        Catch e As Exception
            ' Clear the RSA key.
        End Try

    End Sub

    Sub Encrypt(ByVal Doc As XmlDocument, ByVal ElementToEncryptParam 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 ElementToEncryptParam 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 elementToEncrypt As XmlElement = Doc.GetElementsByTagName(ElementToEncryptParam)(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(elementToEncrypt, 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.

        ' 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)

    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.

    End Sub

    Sub InspectElement(ByVal Doc As XmlDocument)
        ' Get the EncryptedKey element from the XMLDocument object.
        Dim encryptedKey As XmlElement = Doc.GetElementsByTagName("EncryptedKey")(0)

        ' Create a new EncryptedKey object.
        Dim k As New EncryptedKey()

        ' Load the XML from the document to
        ' initialize the EncryptedKey object.

        ' Display the properties.
        ' Most values are Null by default.
        Console.WriteLine("EncryptedKey.KeyInfo: " + k.KeyInfo.GetXml().InnerXml)
        Console.WriteLine("EncryptedKey.Id: " + k.Id)
        Console.WriteLine("EncryptedKey.CarriedKeyName: " + k.CarriedKeyName)
        Console.WriteLine("EncryptedKey.CipherData: " + k.CipherData.GetXml().InnerXml)
        Console.WriteLine("EncryptedKey.Encoding: " + k.Encoding)
        Console.WriteLine("EncryptedKey.EncryptionMethod: " + k.EncryptionMethod.GetXml().InnerXml)
        If k.EncryptionProperties.Count >= 1 Then
            Console.WriteLine("EncryptedKey.EncryptionProperties: " + k.EncryptionProperties(0).GetXml().InnerXml)
        End If
        Console.WriteLine("EncryptedKey.MimeType: " + k.MimeType)
        Console.WriteLine("EncryptedKey.Recipient: " + k.Recipient)

        If k.ReferenceList.Count >= 1 Then
            Console.WriteLine("EncryptedKey.ReferenceList: " + k.ReferenceList(0).GetXml().InnerXml)
        End If

    End Sub
End Module


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