EncryptionProperty Class
Assembly: System.Security (in system.security.dll)
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.
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) 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() Try ' Encrypt the "creditcard" element. Encrypt(xmlDoc, "creditcard", rsaKey, "rsaKey") ' Inspect the EncryptedKey element. InspectElement(xmlDoc) ' Decrypt the "creditcard" element. Decrypt(xmlDoc, rsaKey, "rsaKey") 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 ElementToEncryptValue 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 ElementToEncryptValue 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(ElementToEncryptValue)(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) ' 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. Dim element As XmlElement = 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. Dim encProp As New EncryptionProperty(element) ' Add the EncryptionProperty object to the EncryptedData object. edElement.AddProperty(encProp) ' 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(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. exml.DecryptDocument() End Sub Sub InspectElement(ByVal Doc As XmlDocument) ' Get the EncryptedData element from the XMLDocument object. Dim encryptedData As XmlElement = Doc.GetElementsByTagName("EncryptedData")(0) ' Create a new EncryptedData object. Dim encData As New EncryptedData() ' Load the XML from the document to ' initialize the EncryptedData object. encData.LoadXml(encryptedData) ' 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) Dim encPropCollection As EncryptionPropertyCollection = encData.EncryptionProperties Console.WriteLine("Number of elements in the EncryptionPropertyCollection: " + encPropCollection.Count.ToString()) 'encPropCollection. Dim encProp As EncryptionProperty For Each encProp In encPropCollection Console.WriteLine("EncryptionProperty.ID: " + encProp.Id) Console.WriteLine("EncryptionProperty.PropertyElement: " + encProp.PropertyElement.InnerXml) Console.WriteLine("EncryptionProperty.Target: " + encProp.Target) Next encProp Console.WriteLine("EncryptedData.Id: " + encData.Id) Console.WriteLine("EncryptedData.KeyInfo: " + encData.KeyInfo.GetXml().InnerXml) Console.WriteLine("EncryptedData.MimeType: " + encData.MimeType) End Sub End Module
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.