ProtectedConfigurationProvider Class
Definition
Important
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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
- 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). For more information, see Implementing a Protected Configuration Provider.
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.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
' 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
' 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
' 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
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.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
' 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
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
End Class
End Namespace
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.
.NET 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() |
Initializes a new instance of the ProtectedConfigurationProvider class using default settings. |
Properties
Description |
Gets a brief, friendly description suitable for display in administrative tools or other user interfaces (UIs). (Inherited from ProviderBase) |
Name |
Gets the friendly name used to refer to the provider during configuration. (Inherited from ProviderBase) |
Methods
Decrypt(XmlNode) |
Decrypts the passed XmlNode object from a configuration file. |
Encrypt(XmlNode) |
Encrypts the passed XmlNode object from a configuration file. |
Equals(Object) |
Determines whether the specified object is equal to the current object. (Inherited from Object) |
GetHashCode() |
Serves as the default hash function. (Inherited from Object) |
GetType() |
Gets the Type of the current instance. (Inherited from Object) |
Initialize(String, NameValueCollection) |
Initializes the configuration builder. (Inherited from ProviderBase) |
MemberwiseClone() |
Creates a shallow copy of the current Object. (Inherited from Object) |
ToString() |
Returns a string that represents the current object. (Inherited from Object) |