XmlDsigBase64Transform Classe

Definição

Namespace:

System.Security.Cryptography.Xml

Assembly:

System.Security.dll

Representa a Base64 transformação de decodificação conforme definido na Seção 6.6.2 da especificação XMLDSIG.

public ref class XmlDsigBase64Transform : System::Security::Cryptography::Xml::Transform

public class XmlDsigBase64Transform : System.Security.Cryptography.Xml.Transform

type XmlDsigBase64Transform = class
    inherit Transform

Public Class XmlDsigBase64Transform
Inherits Transform

Herança

Object

Transform

XmlDsigBase64Transform

Exemplos

O exemplo de código a seguir demonstra como usar membros da XmlDsigBase64Transform classe.

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

class Class1
{
    [STAThread]
    static void Main(string[] args)
    {
        // Encrypt an XML message
        EncryptXML(LoadXMLDoc());

        // Using XmlDsigBase64Transform resolving a Uri.
        Uri baseUri = new Uri("http://www.microsoft.com");
        string relativeUri = "msdn";
        Uri absoluteUri = ResolveUris(baseUri, relativeUri);

        Console.WriteLine("This sample completed successfully; " +
            "press Enter to exit.");
        Console.ReadLine();
    }

    // Encrypt the text in the specified XmlDocument.
    private static void EncryptXML(XmlDocument xmlDoc)
    {
        XmlDsigBase64Transform xmlTransform = new XmlDsigBase64Transform();

        // Ensure the transform is using the proper algorithm.
        xmlTransform.Algorithm = SignedXml.XmlDsigBase64TransformUrl;

        // Retrieve the XML representation of the current transform.
        XmlElement xmlInTransform = xmlTransform.GetXml();

        Console.WriteLine("Xml representation of the current transform: ");
        Console.WriteLine(xmlInTransform.OuterXml);

        // Retrieve the valid input types for the current transform.
        Type[] validInTypes = xmlTransform.InputTypes;

        // Verify the xmlTransform can accept the XMLDocument as an
        // input type.
        for (int i=0; i<validInTypes.Length; i++)
        {
            if (validInTypes[i] == xmlDoc.GetType())
            {
                // Demonstrate loading the entire Xml Document.
                xmlTransform.LoadInput(xmlDoc);

                // This transform is created for demonstration purposes.
                XmlDsigBase64Transform secondTransform =
                    new XmlDsigBase64Transform();

                string classDescription = secondTransform.ToString();

                // This call does not perform as expected.
                // LoadInnerXml is overridden by the XmlDsigBase64Transform
                // class, but is stubbed out.
                secondTransform.LoadInnerXml(xmlDoc.SelectNodes("//."));

                break;
            }
        }

        Type[] validOutTypes = xmlTransform.OutputTypes;

        for (int i=0; i<validOutTypes.Length; i++)
        {
            if (validOutTypes[i] == typeof(System.IO.Stream))
            {
                try 
                {
                    Type streamType = typeof(System.IO.Stream);
                    CryptoStream outputStream = (CryptoStream) 
                        xmlTransform.GetOutput(streamType);

                    // Read the CryptoStream into a stream reader.
                    StreamReader streamReader =
                        new StreamReader(outputStream);

                    // Read the stream into a string.
                    string outputMessage = streamReader.ReadToEnd();

                    // Close the streams.
                    outputStream.Close();
                    streamReader.Close();

                    // Display to the console the Xml before and after
                    // encryption.
                    Console.WriteLine("Encoding the following message: " +
                        xmlDoc.InnerText);
                    Console.WriteLine("Message encoded: " + outputMessage);
            }
                catch (Exception ex)
                {
                    Console.WriteLine("Unexpected exception caught: " +
                        ex.ToString());
                }

                break;
            }
            else
            {
                object outputObject = xmlTransform.GetOutput();
            }
        }
    }

    // Create an XML document with Element and Text nodes.
    private static XmlDocument LoadXMLDoc()
    {
        XmlDocument xmlDoc = new XmlDocument();

        XmlNode mainNode = xmlDoc.CreateNode(
            XmlNodeType.Element,
            "ContosoMessages",
            "http://www.contoso.com");

        XmlNode textNode = xmlDoc.CreateTextNode("Some text to encode.");
        mainNode.AppendChild(textNode);
        xmlDoc.AppendChild(mainNode);

        Console.WriteLine("Created the following XML Document for " +
            "transformation: ");
        Console.WriteLine(xmlDoc.InnerXml);
        return xmlDoc;
    }

    // Resolve the specified base and relative Uri's .
    private static Uri ResolveUris(Uri baseUri, string relativeUri)
    {
        XmlUrlResolver xmlResolver = new XmlUrlResolver();
        xmlResolver.Credentials = 
            System.Net.CredentialCache.DefaultCredentials;

        XmlDsigBase64Transform xmlTransform = new XmlDsigBase64Transform();
        xmlTransform.Resolver = xmlResolver;

        Uri absoluteUri = xmlResolver.ResolveUri(baseUri, relativeUri);

        if (absoluteUri != null)
        {
            Console.WriteLine(
                "Resolved the base Uri and relative Uri to the following:");
            Console.WriteLine(absoluteUri.ToString());
        }
        else
        {
            Console.WriteLine(
                "Unable to resolve the base Uri and relative Uri");
        }
        return absoluteUri;
    }
}
//
// This sample produces the following output:
//
// Created the following XML Document for transformation:
// <ContosoMessages xmlns="http://www.contoso.com">Some text to encode.
// Xml representation of the current transform:
// <Transform Algorithm="http://www.w3.org/2000/09/xmldsig#base64" xmlns=
// "http://www.w3.org/2000/09/xmldsig#" />
// Encoding the following message: Some text to encode.
// Message encoded: Jmr^
// Resolved the base Uri and relative Uri to the following:
// http://www.microsoft.com/msdn
// This sample completed successfully; press Enter to exit.

Imports System.IO
Imports System.Xml
Imports System.Security.Cryptography
Imports System.Security.Cryptography.Xml


Public Class Form1
    Inherits System.Windows.Forms.Form

    ' Event handler for Run button.
    Private Sub Button1_Click( _
        ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles Button1.Click

        tbxOutput.Cursor = Cursors.WaitCursor
        tbxOutput.Text = ""

        ' Encrypt an XML message
        EncryptXML(LoadXMLDoc())

        ' Using XmlDsigBase64Transform resolving a Uri.
        Dim baseUri As New Uri("http://www.microsoft.com")
        Dim relativeUri As String = "msdn"
        Dim absoluteUri As Uri = ResolveUris(baseUri, relativeUri)

        ' Reset the cursor and conclude application.
        WriteLine(vbCrLf + "This sample completed successfully;" + _
            " press Exit to continue.")
        tbxOutput.Cursor = Cursors.Default
    End Sub

    ' Encrypt the text in the specified XmlDocument.
    Private Sub EncryptXML(ByVal xmlDoc As XmlDocument)
        Dim xmlTransform As New XmlDsigBase64Transform

        ' Ensure the transform is using the proper algorithm.
        xmlTransform.Algorithm = SignedXml.XmlDsigBase64TransformUrl

        ' Retrieve the XML representation of the current transform.
        Dim xmlInTransform As XmlElement = xmlTransform.GetXml()

        WriteLine("Xml representation of the current transform: ")
        WriteLine(xmlInTransform.OuterXml)

        ' Retrieve the valid input types for the current transform.
        Dim validInTypes() As Type = xmlTransform.InputTypes

        ' Verify the xmlTransform can accept the XMLDocument as an
        ' input type.
        For i As Int16 = 0 To validInTypes.Length Step 1
            If (validInTypes(i).Equals(xmlDoc.GetType())) Then
                ' Demonstrate loading the entire Xml Document.
                xmlTransform.LoadInput(xmlDoc)

                ' This transform is created for demonstration purposes.
                Dim secondTransform As New XmlDsigBase64Transform

                Dim classDescription As String = secondTransform.ToString()

                ' This call does not perform as expected.
                ' LoadInnerXml is overridden by the XmlDsigBase64Transform
                ' class, but is stubbed out.
                secondTransform.LoadInnerXml(xmlDoc.SelectNodes("//."))

                Exit For
            End If
        Next
        Dim validOutTypes() As Type = xmlTransform.OutputTypes

        For i As Int16 = 0 To validOutTypes.Length Step 1
            If (validOutTypes(i).equals(GetType(System.IO.Stream))) Then
                Try
                    Dim streamType As Type = GetType(System.IO.Stream)

                    Dim outputStream As CryptoStream
                    outputStream = CType( _
                        xmlTransform.GetOutput(streamType), _
                        CryptoStream)


                    ' Read the CryptoStream into a stream reader.
                    Dim streamReader As New StreamReader(outputStream)

                    ' Read the stream into a string.
                    Dim outputMessage As String = streamReader.ReadToEnd()

                    ' Close the streams.
                    outputStream.Close()
                    streamReader.Close()

                    ' Display to the console the Xml before and after
                    ' encryption.
                    WriteLine("Encoding the following message: " + _
                        xmlDoc.InnerText)
                    WriteLine("Message encoded: " + outputMessage)

                Catch ex As Exception
                    WriteLine("Unexpected exception caught: " + _
                        ex.ToString())

                End Try

                ' Stop cycling through types, exit operation.
                Exit For
            Else
                Dim outputObject As Object = xmlTransform.GetOutput()
            End If
        Next
    End Sub

    ' Create an XML document with Element and Text nodes.
    Private Function LoadXMLDoc() As XmlDocument
        Dim xmlDoc As New XmlDocument

        Dim mainNode As XmlNode = xmlDoc.CreateNode( _
            XmlNodeType.Element, _
            "ContosoMessages", _
            "http://www.contoso.com")

        Dim textNode As XmlNode
        textNode = xmlDoc.CreateTextNode("Some text to encode.")
        mainNode.AppendChild(textNode)
        xmlDoc.AppendChild(mainNode)

        WriteLine("Created the following XML Document for " + _
            "transformation: ")
        WriteLine(xmlDoc.InnerXml)
        Return xmlDoc
    End Function

    ' Resolve the specified base and relative Uri's .
    Private Function ResolveUris( _
        ByVal baseUri As Uri, _
        ByVal relativeUri As String) As Uri

        Dim xmlResolver As New XmlUrlResolver
        xmlResolver.Credentials = _
            System.Net.CredentialCache.DefaultCredentials

        Dim xmlTransform As New XmlDsigBase64Transform
        xmlTransform.Resolver = xmlResolver

        Dim absoluteUri As Uri = _
            xmlResolver.ResolveUri(baseUri, relativeUri)

        If Not absoluteUri Is Nothing Then
            WriteLine( _
                "Resolved the base Uri and relative Uri to the following:")
            WriteLine(absoluteUri.ToString())
        Else
            WriteLine("Unable to resolve the base Uri and relative Uri")
        End If
        Return absoluteUri
    End Function

    ' Write message and carriage return to the output textbox.
    Private Sub WriteLine(ByVal message As String)
        tbxOutput.AppendText(message + vbCrLf)
    End Sub

    ' Event handler for Exit button.
    Private Sub Button2_Click( _
        ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles Button2.Click

        Application.Exit()
    End Sub
#Region " Windows Form Designer generated code "

    Public Sub New()
        MyBase.New()

        'This call is required by the Windows Form Designer.
        InitializeComponent()

        'Add any initialization after the InitializeComponent() call

    End Sub

    'Form overrides dispose to clean up the component list.
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing Then
            If Not (components Is Nothing) Then
                components.Dispose()
            End If
        End If
        MyBase.Dispose(disposing)
    End Sub

    'Required by the Windows Form Designer
    Private components As System.ComponentModel.IContainer

    'NOTE: The following procedure is required by the Windows Form Designer
    'It can be modified using the Windows Form Designer.  
    'Do not modify it using the code editor.
    Friend WithEvents Panel2 As System.Windows.Forms.Panel
    Friend WithEvents Panel1 As System.Windows.Forms.Panel
    Friend WithEvents Button1 As System.Windows.Forms.Button
    Friend WithEvents Button2 As System.Windows.Forms.Button
    Friend WithEvents tbxOutput As System.Windows.Forms.RichTextBox
    <System.Diagnostics.DebuggerStepThrough()> _
    Private Sub InitializeComponent()
        Me.Panel2 = New System.Windows.Forms.Panel
        Me.Button1 = New System.Windows.Forms.Button
        Me.Button2 = New System.Windows.Forms.Button
        Me.Panel1 = New System.Windows.Forms.Panel
        Me.tbxOutput = New System.Windows.Forms.RichTextBox
        Me.Panel2.SuspendLayout()
        Me.Panel1.SuspendLayout()
        Me.SuspendLayout()
        '
        'Panel2
        '
        Me.Panel2.Controls.Add(Me.Button1)
        Me.Panel2.Controls.Add(Me.Button2)
        Me.Panel2.Dock = System.Windows.Forms.DockStyle.Bottom
        Me.Panel2.DockPadding.All = 20
        Me.Panel2.Location = New System.Drawing.Point(0, 320)
        Me.Panel2.Name = "Panel2"
        Me.Panel2.Size = New System.Drawing.Size(616, 64)
        Me.Panel2.TabIndex = 1
        '
        'Button1
        '
        Me.Button1.Dock = System.Windows.Forms.DockStyle.Right
        Me.Button1.Font = New System.Drawing.Font( _
            "Microsoft Sans Serif", _
            9.0!, _
            System.Drawing.FontStyle.Regular, _
            System.Drawing.GraphicsUnit.Point, _
            CType(0, Byte))
        Me.Button1.Location = New System.Drawing.Point(446, 20)
        Me.Button1.Name = "Button1"
        Me.Button1.Size = New System.Drawing.Size(75, 24)
        Me.Button1.TabIndex = 2
        Me.Button1.Text = "&Run"
        '
        'Button2
        '
        Me.Button2.Dock = System.Windows.Forms.DockStyle.Right
        Me.Button2.Font = New System.Drawing.Font( _
            "Microsoft Sans Serif", _
            9.0!, _
            System.Drawing.FontStyle.Regular, _
            System.Drawing.GraphicsUnit.Point, _
            CType(0, Byte))
        Me.Button2.Location = New System.Drawing.Point(521, 20)
        Me.Button2.Name = "Button2"
        Me.Button2.Size = New System.Drawing.Size(75, 24)
        Me.Button2.TabIndex = 3
        Me.Button2.Text = "E&xit"
        '
        'Panel1
        '
        Me.Panel1.Controls.Add(Me.tbxOutput)
        Me.Panel1.Dock = System.Windows.Forms.DockStyle.Fill
        Me.Panel1.DockPadding.All = 20
        Me.Panel1.Location = New System.Drawing.Point(0, 0)
        Me.Panel1.Name = "Panel1"
        Me.Panel1.Size = New System.Drawing.Size(616, 320)
        Me.Panel1.TabIndex = 2
        '
        'tbxOutput
        '
        Me.tbxOutput.AccessibleDescription = _
            "Displays output from application."
        Me.tbxOutput.AccessibleName = "Output textbox."
        Me.tbxOutput.Dock = System.Windows.Forms.DockStyle.Fill
        Me.tbxOutput.Location = New System.Drawing.Point(20, 20)
        Me.tbxOutput.Name = "tbxOutput"
        Me.tbxOutput.Size = New System.Drawing.Size(576, 280)
        Me.tbxOutput.TabIndex = 1
        Me.tbxOutput.Text = "Click the Run button to run the application."
        '
        'Form1
        '
        Me.AutoScaleBaseSize = New System.Drawing.Size(6, 15)
        Me.ClientSize = New System.Drawing.Size(616, 384)
        Me.Controls.Add(Me.Panel1)
        Me.Controls.Add(Me.Panel2)
        Me.Name = "Form1"
        Me.Text = "XmlDsigBase64Transform"
        Me.Panel2.ResumeLayout(False)
        Me.Panel1.ResumeLayout(False)
        Me.ResumeLayout(False)

    End Sub

#End Region
End Class
'
' This sample produces the following output:
'
' Created the following XML Document for transformation: 
' <ContosoMessages xmlns="http://www.contoso.com">Some text to encode.
' Xml representation of the current transform: 
' <Transform Algorithm="http://www.w3.org/2000/09/xmldsig#base64" xmlns=
' "http://www.w3.org/2000/09/xmldsig#" />
' Encoding the following message: Some text to encode.
' Message encoded: Jmr^
' Resolved the base Uri and relative Uri to the following:
' http://www.microsoft.com/msdn
' 
' This sample completed successfully; press Exit to continue.

Comentários

Use o XmlDsigBase64Transform objeto quando precisar assinar os dados brutos associados ao conteúdo codificado de um elemento.

O URI (Uniform Resource Identifier) que descreve o XmlDsigBase64Transform objeto é definido pelo XmlDsigBase64TransformUrl campo.

Para obter mais informações sobre a Base64 transformação de decodificação, consulte a Seção 6.6.2 da especificação W3C XMLDSIG.

Construtores

Nome	Description
XmlDsigBase64Transform()	Inicializa uma nova instância da classe XmlDsigBase64Transform.

Propriedades

Nome	Description
Algorithm	Obtém ou define o URI (Uniform Resource Identifier) que identifica o algoritmo executado pela transformação atual. (Herdado de Transform)
Context	Obtém ou define um XmlElement objeto que representa o contexto do documento no qual o objeto atual Transform está em execução. (Herdado de Transform)
InputTypes	Obtém uma matriz de tipos que são entradas válidas para o LoadInput(Object) método do objeto atual XmlDsigBase64Transform .
OutputTypes	Obtém uma matriz de tipos que são possíveis saídas dos GetOutput() métodos do objeto atual XmlDsigBase64Transform .
PropagatedNamespaces	Obtém ou define um Hashtable objeto que contém os namespaces propagados para a assinatura. (Herdado de Transform)
Resolver	Define o objeto atual XmlResolver . (Herdado de Transform)

Métodos

Nome	Description
Equals(Object)	Determina se o objeto especificado é igual ao objeto atual. (Herdado de Object)
GetDigestedOutput(HashAlgorithm)	Quando substituído em uma classe derivada, retorna o resumo associado a um Transform objeto. (Herdado de Transform)
GetHashCode()	Serve como a função hash predefinida. (Herdado de Object)
GetInnerXml()	Retorna uma representação XML dos parâmetros do XmlDsigBase64Transform objeto que são adequados para serem incluídos como subelementos de um elemento XMLDSIG <Transform> .
GetOutput()	Retorna a saída do objeto atual XmlDsigBase64Transform .
GetOutput(Type)	Retorna a saída do objeto atual XmlDsigBase64Transform do tipo Stream.
GetType()	Obtém o Type da instância atual. (Herdado de Object)
GetXml()	Retorna a representação XML do objeto atual Transform . (Herdado de Transform)
LoadInnerXml(XmlNodeList)	Analisa o objeto especificado XmlNodeList como conteúdo específico da transformação de um <Transform> elemento; esse método não tem suporte porque o XmlDsigBase64Transform objeto não tem elementos XML internos.
LoadInput(Object)	Carrega a entrada especificada no objeto atual XmlDsigBase64Transform .
MemberwiseClone()	Cria uma cópia superficial do Objectatual. (Herdado de Object)
ToString()	Retorna uma cadeia de caracteres que representa o objeto atual. (Herdado de Object)