ProtectedConfigurationProvider ProtectedConfigurationProvider ProtectedConfigurationProvider ProtectedConfigurationProvider Class

Definition

Is the base class to create providers for encrypting and decrypting protected-configuration data.

public ref class ProtectedConfigurationProvider abstract : System::Configuration::Provider::ProviderBase
public abstract class ProtectedConfigurationProvider : System.Configuration.Provider.ProviderBase
type ProtectedConfigurationProvider = class
    inherit ProviderBase
Public MustInherit Class ProtectedConfigurationProvider
Inherits ProviderBase
Inheritance
ProtectedConfigurationProviderProtectedConfigurationProviderProtectedConfigurationProviderProtectedConfigurationProvider
Derived

Examples

The following example shows how to implement a custom ProtectedConfigurationProvider.

To be able to configure this provider, as shown in the next configuration excerpt, you must install it in the Global Assembly Cache (GAC). Refer to Implementing a Protected Configuration Provider for more information.

using System;
using System.Xml;
using System.Security.Cryptography;
using System.IO;
using System.Text;
using System.Configuration.Provider;
using System.Collections.Specialized;
using System.Configuration;

namespace Samples.AspNet
{
    // Shows how to create a custom protected configuration
    // provider.
    public class TripleDESProtectedConfigurationProvider :
        ProtectedConfigurationProvider
    {

        private TripleDESCryptoServiceProvider des =
            new TripleDESCryptoServiceProvider();

        private string pKeyFilePath;
        private string pName;

        // Gets the path of the file
        // containing the key used to
        // encryption or decryption.
        public string KeyFilePath
        {
            get { return pKeyFilePath; }
        }


        // Gets the provider name.
        public override string Name
        {
            get { return pName; }
        }


        // Performs provider initialization.
        public override void Initialize(string name,
            NameValueCollection config)
        {
            pName = name;
            pKeyFilePath = config["keyContainerName"];
            ReadKey(KeyFilePath);
        }


        // Performs encryption.
        public override XmlNode Encrypt(XmlNode node)
        {
            string encryptedData = EncryptString(node.OuterXml);

            XmlDocument xmlDoc = new XmlDocument();
            xmlDoc.PreserveWhitespace = true;
            xmlDoc.LoadXml("<EncryptedData>" +
                encryptedData + "</EncryptedData>");

            return xmlDoc.DocumentElement;
        }

        // Performs decryption.
        public override XmlNode Decrypt(XmlNode encryptedNode)
        {
            string decryptedData =
                DecryptString(encryptedNode.InnerText);

            XmlDocument xmlDoc = new XmlDocument();
            xmlDoc.PreserveWhitespace = true;
            xmlDoc.LoadXml(decryptedData);

            return xmlDoc.DocumentElement;
        }

        // Encrypts a configuration section and returns 
        // the encrypted XML as a string.
        private string EncryptString(string encryptValue)
        {
            byte[] valBytes =
                Encoding.Unicode.GetBytes(encryptValue);

            ICryptoTransform transform = des.CreateEncryptor();

            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms,
                transform, CryptoStreamMode.Write);
            cs.Write(valBytes, 0, valBytes.Length);
            cs.FlushFinalBlock();
            byte[] returnBytes = ms.ToArray();
            cs.Close();

            return Convert.ToBase64String(returnBytes);
        }


        // Decrypts an encrypted configuration section and 
        // returns the unencrypted XML as a string.
        private string DecryptString(string encryptedValue)
        {
            byte[] valBytes =
                Convert.FromBase64String(encryptedValue);

            ICryptoTransform transform = des.CreateDecryptor();

            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms,
                transform, CryptoStreamMode.Write);
            cs.Write(valBytes, 0, valBytes.Length);
            cs.FlushFinalBlock();
            byte[] returnBytes = ms.ToArray();
            cs.Close();

            return Encoding.Unicode.GetString(returnBytes);
        }

        // Generates a new TripleDES key and vector and 
        // writes them to the supplied file path.
        public void CreateKey(string filePath)
        {
            des.GenerateKey();
            des.GenerateIV();

            StreamWriter sw = new StreamWriter(filePath, false);
            sw.WriteLine(ByteToHex(des.Key));
            sw.WriteLine(ByteToHex(des.IV));
            sw.Close();
        }


        // Reads in the TripleDES key and vector from 
        // the supplied file path and sets the Key 
        // and IV properties of the 
        // TripleDESCryptoServiceProvider.
        private void ReadKey(string filePath)
        {
            StreamReader sr = new StreamReader(filePath);
            string keyValue = sr.ReadLine();
            string ivValue = sr.ReadLine();
            des.Key = HexToByte(keyValue);
            des.IV = HexToByte(ivValue);
        }


        // Converts a byte array to a hexadecimal string.
        private string ByteToHex(byte[] byteArray)
        {
            string outString = "";

            foreach (Byte b in byteArray)
                outString += b.ToString("X2");

            return outString;
        }

        // Converts a hexadecimal string to a byte array.
        private byte[] HexToByte(string hexString)
        {
            byte[] returnBytes = new byte[hexString.Length / 2];
            for (int i = 0; i < returnBytes.Length; i++)
                returnBytes[i] =
                    Convert.ToByte(hexString.Substring(i * 2, 2), 16);
            return returnBytes;
        }

    }

}
Imports System
Imports System.Xml
Imports System.Security.Cryptography
Imports System.IO
Imports System.Text
Imports System.Configuration.Provider
Imports System.Collections.Specialized
Imports System.Configuration


' Shows how to create a custom protected configuration
' provider.
Namespace Samples.AspNet

    Public Class TripleDESProtectedConfigurationProvider
        Inherits ProtectedConfigurationProvider

        Private des _
        As New TripleDESCryptoServiceProvider()

        Private pKeyFilePath As String
        Private pName As String

        ' Gets the path of the file
        ' containing the key used to
        ' encrypt/decrypt.

        Public ReadOnly Property KeyFilePath() As String
            Get
                Return pKeyFilePath
            End Get
        End Property

        ' Gets the provider name.

        Public Overrides ReadOnly Property Name() As String
            Get
                Return pName
            End Get
        End Property


        ' Performs provider initialization.
        Public Overrides Sub Initialize( _
        ByVal name As String, _
        ByVal config As NameValueCollection)
            pName = name
            pKeyFilePath = config("keyContainerName")
            ReadKey(KeyFilePath)
        End Sub 'Initialize


        ' Performs encryption.
        Public Overrides Function Encrypt( _
        ByVal node As XmlNode) As XmlNode
            Dim encryptedData As String = _
            EncryptString(node.OuterXml)

            Dim xmlDoc As New XmlDocument()
            xmlDoc.PreserveWhitespace = True
            xmlDoc.LoadXml( _
            ("<EncryptedData>" + encryptedData + _
            "</EncryptedData>"))

            Return xmlDoc.DocumentElement
        End Function 'Encrypt

        ' Performs decryption.
        Public Overrides Function Decrypt( _
        ByVal encryptedNode As XmlNode) As XmlNode
            Dim decryptedData As String = _
            DecryptString(encryptedNode.InnerText)

            Dim xmlDoc As New XmlDocument()
            xmlDoc.PreserveWhitespace = True
            xmlDoc.LoadXml(decryptedData)

            Return xmlDoc.DocumentElement
        End Function 'Decrypt



        ' Encrypts a configuration section and returns 
        ' the encrypted XML as a string.
        Private Function EncryptString( _
        ByVal encryptValue As String) As String
            Dim valBytes As Byte() = _
            Encoding.Unicode.GetBytes(encryptValue)

            Dim transform As ICryptoTransform = _
            des.CreateEncryptor()

            Dim ms As New MemoryStream()
            Dim cs As New CryptoStream(ms, _
            transform, CryptoStreamMode.Write)
            cs.Write(valBytes, 0, valBytes.Length)
            cs.FlushFinalBlock()
            Dim returnBytes As Byte() = ms.ToArray()
            cs.Close()

            Return Convert.ToBase64String(returnBytes)
        End Function 'EncryptString



        ' Decrypts an encrypted configuration section and 
        ' returns the unencrypted XML as a string.
        Private Function DecryptString( _
        ByVal encryptedValue As String) As String
            Dim valBytes As Byte() = _
            Convert.FromBase64String(encryptedValue)

            Dim transform As ICryptoTransform = _
            des.CreateDecryptor()

            Dim ms As New MemoryStream()
            Dim cs As New CryptoStream(ms, _
            transform, CryptoStreamMode.Write)
            cs.Write(valBytes, 0, valBytes.Length)
            cs.FlushFinalBlock()
            Dim returnBytes As Byte() = ms.ToArray()
            cs.Close()

            Return Encoding.Unicode.GetString(returnBytes)
        End Function 'DecryptString


        ' Generates a new TripleDES key and vector and 
        ' writes them to the supplied file path.
        Public Sub CreateKey(ByVal filePath As String)
            des.GenerateKey()
            des.GenerateIV()

            Dim sw As New StreamWriter(filePath, False)
            sw.WriteLine(ByteToHex(des.Key))
            sw.WriteLine(ByteToHex(des.IV))
            sw.Close()
        End Sub 'CreateKey



        ' Reads in the TripleDES key and vector from 
        ' the supplied file path and sets the Key 
        ' and IV properties of the 
        ' TripleDESCryptoServiceProvider.
        Private Sub ReadKey(ByVal filePath As String)
            Dim sr As New StreamReader(filePath)
            Dim keyValue As String = sr.ReadLine()
            Dim ivValue As String = sr.ReadLine()
            des.Key = HexToByte(keyValue)
            des.IV = HexToByte(ivValue)
        End Sub 'ReadKey



        ' Converts a byte array to a hexadecimal string.
        Private Function ByteToHex( _
        ByVal byteArray() As Byte) As String
            Dim outString As String = ""

            Dim b As [Byte]
            For Each b In byteArray
                outString += b.ToString("X2")
            Next b
            Return outString
        End Function 'ByteToHex


        ' Converts a hexadecimal string to a byte array.
        Private Function HexToByte(ByVal hexString As String) As Byte()
            Dim returnBytes(hexString.Length / 2) As Byte
            Dim i As Integer
            For i = 0 To returnBytes.Length - 1
                returnBytes(i) = _
                Convert.ToByte(hexString.Substring(i * 2, 2), 16)
            Next i
            Return returnBytes
        End Function 'HexToByte
    End Class 'TripleDESProtectedConfigurationProvider 

End Namespace

The following example shows how to use the previous custom ProtectedConfigurationProvider.

using System;
using System.Configuration;
using Samples.AspNet.Configuration;

namespace Samples.AspNet.Configuration
{

    // Show how to use a custom protected configuration
    // provider.
    public class TestingProtectedConfigurationProvider
    {

        // Protect the connectionStrings section.
        private static void ProtectConfiguration()
        {

            // Get the application configuration file.
            System.Configuration.Configuration config =
                    ConfigurationManager.OpenExeConfiguration(
                    ConfigurationUserLevel.None);

            // Define the provider name.
            string provider =
                "TripleDESProtectedConfigurationProvider";

            // Get the section to protect.
            ConfigurationSection connStrings =
                config.ConnectionStrings;

            if (connStrings != null)
            {
                if (!connStrings.SectionInformation.IsProtected)
                {
                    if (!connStrings.ElementInformation.IsLocked)
                    {
                        // Protect the section.
                        connStrings.SectionInformation.ProtectSection(provider);

                        connStrings.SectionInformation.ForceSave = true;
                        config.Save(ConfigurationSaveMode.Full);

                        Console.WriteLine("Section {0} is now protected by {1}",
                            connStrings.SectionInformation.Name,
                            connStrings.SectionInformation.ProtectionProvider.Name);

                    }
                    else
                        Console.WriteLine(
                             "Can't protect, section {0} is locked",
                             connStrings.SectionInformation.Name);
                }
                else
                    Console.WriteLine(
                        "Section {0} is already protected by {1}",
                        connStrings.SectionInformation.Name,
                        connStrings.SectionInformation.ProtectionProvider.Name);

            }
            else
                Console.WriteLine("Can't get the section {0}",
                    connStrings.SectionInformation.Name);

        }

        // Unprotect the connectionStrings section.
        private static void UnProtectConfiguration()
        {

            // Get the application configuration file.
            System.Configuration.Configuration config =
                    ConfigurationManager.OpenExeConfiguration(
                    ConfigurationUserLevel.None);

            // Get the section to unprotect.
            ConfigurationSection connStrings =
                config.ConnectionStrings;

            if (connStrings != null)
            {
                if (connStrings.SectionInformation.IsProtected)
                {
                    if (!connStrings.ElementInformation.IsLocked)
                    {
                        // Unprotect the section.
                        connStrings.SectionInformation.UnprotectSection();

                        connStrings.SectionInformation.ForceSave = true;
                        config.Save(ConfigurationSaveMode.Full);

                        Console.WriteLine("Section {0} is now unprotected.",
                            connStrings.SectionInformation.Name);

                    }
                    else
                        Console.WriteLine(
                             "Can't unprotect, section {0} is locked",
                             connStrings.SectionInformation.Name);
                }
                else
                    Console.WriteLine(
                        "Section {0} is already unprotected.",
                        connStrings.SectionInformation.Name);

            }
            else
                Console.WriteLine("Can't get the section {0}",
                    connStrings.SectionInformation.Name);

        }


        public static void Main(string[] args)
        {

            string selection = string.Empty;

            if (args.Length == 0)
            {
                Console.WriteLine(
                    "Select createkey, protect or unprotect");
                return;
            }

            selection = args[0].ToLower();

            switch (selection)
            {

                // Create the key to use during 
                // encryption/decryption.
                case "createkey":
                    string keyContainer = 
                        "pcKey.txt";

                    // Instantiate the custom provider.
                    TripleDESProtectedConfigurationProvider 
                        provider =
                        new TripleDESProtectedConfigurationProvider();

                    // Create the encryption/decryption key.
                    provider.CreateKey(keyContainer);

                    Console.WriteLine(
                        "New TripleDES key created in {0}",
                        keyContainer);
                    break;

                case "protect":
                    ProtectConfiguration();
                    break;

                case "unprotect":
                    UnProtectConfiguration();
                    break;

                default:
                    Console.WriteLine("Unknown selection");
                    break;
            }

            Console.Read();

        }


    }

}
Imports System
Imports System.Configuration

Namespace Samples.AspNet
    ' Show how to use a custom protected configuration
    ' provider.

    Public Class TestingProtectedConfigurationProvider


        ' Protect the connectionStrings section.
        Private Shared Sub ProtectConfiguration()

            ' Get the application configuration file.
            Dim config _
            As System.Configuration.Configuration = _
            ConfigurationManager.OpenExeConfiguration( _
            ConfigurationUserLevel.None)

            ' Define the provider name.
            Dim provider As String = _
            "TripleDESProtectedConfigurationProvider"

            ' Get the section to protect.
            Dim connStrings _
            As ConfigurationSection = config.ConnectionStrings

            If Not (connStrings Is Nothing) Then
                If Not connStrings.SectionInformation.IsProtected Then
                    If Not connStrings.ElementInformation.IsLocked Then
                        ' Protect the section.
                        connStrings.SectionInformation.ProtectSection( _
                        provider)

                        connStrings.SectionInformation.ForceSave = True
                        config.Save(ConfigurationSaveMode.Full)

                        Console.WriteLine( _
                        "Section {0} is now protected by {1}", _
                        connStrings.SectionInformation.Name, _
                        connStrings.SectionInformation.ProtectionProvider.Name)

                    Else
                        Console.WriteLine( _
                        "Can't protect, section {0} is locked", _
                        connStrings.SectionInformation.Name)
                    End If
                Else
                    Console.WriteLine( _
                    "Section {0} is already protected by {1}", _
                    connStrings.SectionInformation.Name, _
                    connStrings.SectionInformation.ProtectionProvider.Name)
                End If

            Else
                Console.WriteLine( _
                "Can't get the section {0}", _
                connStrings.SectionInformation.Name)
            End If
        End Sub 'ProtectConfiguration


        ' Unprotect the connectionStrings section.
        Private Shared Sub UnProtectConfiguration()

            ' Get the application configuration file.
            Dim config _
            As System.Configuration.Configuration = _
            ConfigurationManager.OpenExeConfiguration( _
            ConfigurationUserLevel.None)

            ' Get the section to unprotect.
            Dim connStrings _
            As ConfigurationSection = config.ConnectionStrings

            If Not (connStrings Is Nothing) Then
                If connStrings.SectionInformation.IsProtected Then
                    If Not connStrings.ElementInformation.IsLocked Then
                        ' Unprotect the section.
                        connStrings.SectionInformation.UnprotectSection()

                        connStrings.SectionInformation.ForceSave = True
                        config.Save(ConfigurationSaveMode.Full)

                        Console.WriteLine( _
                        "Section {0} is now unprotected.", _
                        connStrings.SectionInformation.Name)

                    Else
                        Console.WriteLine( _
                        "Can't unprotect, section {0} is locked", _
                        connStrings.SectionInformation.Name)
                    End If
                Else
                    Console.WriteLine( _
                    "Section {0} is already unprotected.", _
                    connStrings.SectionInformation.Name)
                End If

            Else
                Console.WriteLine( _
                "Can't get the section {0}", _
                connStrings.SectionInformation.Name)
            End If
        End Sub 'UnProtectConfiguration



        Public Shared Sub Main(ByVal args() As String)

            Dim selection As String = String.Empty

            If args.Length = 0 Then
                Console.WriteLine( _
                "Select createkey, protect or unprotect")
                Return
            End If

            selection = args(0).ToLower()

            Select Case selection

                ' Create the key to use during 
                ' encryption/decryption.
                Case "createkey"
                    Dim keyContainer As String = "pcKey.txt"

                    ' Instantiate the custom provider.
                    Dim provider _
                    As New TripleDESProtectedConfigurationProvider()

                    ' Create the encryption/decryption key.
                    provider.CreateKey(keyContainer)

                    Console.WriteLine( _
                    "New TripleDES key created in {0}", _
                    keyContainer)

                Case "protect"
                    ProtectConfiguration()

                Case "unprotect"
                    UnProtectConfiguration()

                Case Else
                    Console.WriteLine("Unknown selection")
            End Select

            Console.Read()
        End Sub 'Main 
    End Class 'TestingProtectedConfigurationProvider
End Namespace

The following is an excerpt of the configuration file used by the above examples.

<?xml version="1.0" encoding="utf-8" ?>  
<configuration>  

  <configProtectedData >  
    <providers>  
      <clear />  
      <add keyContainerName="pcKey.txt"   
        name="TripleDESProtectedConfigurationProvider"  
type="Samples.Aspnet.TripleDESProtectedConfigurationProvider, protectedconfigurationproviderlib, Version=1.0.0.0, Culture=neutral, PublicKeyToken=79e01ae0f5cfc66f, processorArchitecture=MSIL" />  
    </providers>  

  </configProtectedData >  

  <connectionStrings>  
    <add name="NorthwindConnectionString"   
      connectionString="Data Source=webnetue2;Initial Catalog=Northwind;User ID=aspnet_test;Password=test"  
providerName="System.Data.SqlClient" />  
  </connectionStrings>  

</configuration>  

Remarks

You can encrypt sections of a configuration file to protect sensitive information used by your application. This improves security by making it difficult for unauthorized access even if an attacker gains access to your configuration file.

The .NET Framework includes two protected configuration providers that can be used to encrypt sections of a configuration file. The RsaProtectedConfigurationProvider class uses the RSACryptoServiceProvider to encrypt configuration sections. The DpapiProtectedConfigurationProvider class uses the Windows Data Protection API (DPAPI) to encrypt configuration sections.

You might have a requirement to encrypt sensitive information using an algorithm other than the RSA or DPAPI providers. In this case, you can build your own custom protected-configuration provider. The ProtectedConfigurationProvider is an abstract base class that you must inherit from to create your own protected-configuration provider.

Whether you use a standard or a custom provider, you must ensure that it is configured with the add element in the providers section of the configProtectedData configuration section. (See next example.)

For details, see Implementing a Protected Configuration Provider.

Note

When ASP.NET encounters encrypted configuration data, it performs decryption transparently using the configured provider. No action is required on your side other than making sure that you configure the required provider.

Constructors

ProtectedConfigurationProvider() ProtectedConfigurationProvider() ProtectedConfigurationProvider() ProtectedConfigurationProvider()

Initializes a new instance of the ProtectedConfigurationProvider class using default settings.

Methods

Decrypt(XmlNode) Decrypt(XmlNode) Decrypt(XmlNode) Decrypt(XmlNode)

Decrypts the passed XmlNode object from a configuration file.

Encrypt(XmlNode) Encrypt(XmlNode) Encrypt(XmlNode) Encrypt(XmlNode)

Encrypts the passed XmlNode object from a configuration file.

Equals(Object) Equals(Object) Equals(Object) Equals(Object)

Determines whether the specified object is equal to the current object.

(Inherited from Object)
GetHashCode() GetHashCode() GetHashCode() GetHashCode()

Serves as the default hash function.

(Inherited from Object)
GetType() GetType() GetType() GetType()

Gets the Type of the current instance.

(Inherited from Object)
Initialize(String, NameValueCollection) Initialize(String, NameValueCollection) Initialize(String, NameValueCollection) Initialize(String, NameValueCollection)

Initializes the configuration builder.

(Inherited from ProviderBase)
MemberwiseClone() MemberwiseClone() MemberwiseClone() MemberwiseClone()

Creates a shallow copy of the current Object.

(Inherited from Object)
ToString() ToString() ToString() ToString()

Returns a string that represents the current object.

(Inherited from Object)

Properties

Description Description Description Description

Gets a brief, friendly description suitable for display in administrative tools or other user interfaces (UIs).

(Inherited from ProviderBase)
Name Name Name Name

Gets the friendly name used to refer to the provider during configuration.

(Inherited from ProviderBase)

Applies to

See Also