Protected Configuration Provider Implementation Example

Article
10/22/2014

The following code example shows how to implement a protected configuration provider. For details about how to build this provider and use it in an ASP.NET application, see How to: Build and Run the Protected Configuration Provider Example.

Example

Code

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


Namespace Samples.AspNet.ProtectedConfiguration

  PublicClass TripleDESProtectedConfigurationProvider
    Inherits ProtectedConfigurationProvider

    Private des As TripleDESCryptoServiceProvider = New TripleDESCryptoServiceProvider()

    Private pKeyFilePath AsStringPrivate pName AsStringPublicReadOnlyProperty KeyFilePath AsStringGetReturn pKeyFilePath
      EndGetEndProperty
    '    ' ProviderBase.Name    'PublicOverridesReadOnlyProperty Name AsStringGetReturn pName
      EndGetEndProperty

    '    ' ProviderBase.Initialize    'PublicOverridesSub Initialize(name AsString, config As NameValueCollection)
      pName = name
      pKeyFilePath = config("keyFilePath")
      ReadKey(KeyFilePath)
    EndSub

    '    ' ProtectedConfigurationProvider.Encrypt    'PublicOverridesFunction Encrypt(node As XmlNode ) As XmlNode 
      Dim encryptedData AsString = EncryptString(node.OuterXml)

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

      Return xmlDoc.DocumentElement
    EndFunction

    '    ' ProtectedConfigurationProvider.Decrypt    'PublicOverridesFunction Decrypt(encryptedNode As XmlNode) As XmlNode
      Dim decryptedData AsString = DecryptString(encryptedNode.InnerText)

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

      Return xmlDoc.DocumentElement
    EndFunction

    '    ' EncryptString    '    Encrypts a configuration section and returns the encrypted    ' XML as a string.    'PrivateFunction EncryptString(encryptValue AsString) AsStringDim valBytes() AsByte = Encoding.Unicode.GetBytes(encryptValue)

      Dim transform As ICryptoTransform = des.CreateEncryptor()

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

      Return Convert.ToBase64String(returnBytes)
    EndFunction

    '    ' DecryptString    '    Decrypts an encrypted configuration section and returns the    ' unencrypted XML as a string.    'PrivateFunction DecryptString(encryptedValue AsString) AsStringDim valBytes() AsByte = Convert.FromBase64String(encryptedValue)

      Dim transform As ICryptoTransform = des.CreateDecryptor()

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

      Return Encoding.Unicode.GetString(returnBytes)
    EndFunction

    '    ' CreateKey    '    Generates a New TripleDES key and vector and writes them    ' to the supplied file path.    'PublicSub CreateKey(filePath AsString)
      des.GenerateKey()
      des.GenerateIV()

      Dim sw As StreamWriter = New StreamWriter(filePath, false)
      sw.WriteLine(ByteToHex(des.Key))
      sw.WriteLine(ByteToHex(des.IV))
      sw.Close()
    EndSub

    '    ' ReadKey    '    Reads in the TripleDES key and vector from the supplied    ' file path and sets the Key and IV properties of the     ' TripleDESCryptoServiceProvider.    'PrivateSub ReadKey(filePath AsString)
      Dim sr As StreamReader = New StreamReader(filePath)
      Dim keyValue AsString = sr.ReadLine()
      Dim ivValue AsString = sr.ReadLine()

      des.Key = HexToByte(keyValue)
      des.IV = HexToByte(ivValue)
    EndSub

    '    ' ByteToHex    '    Converts a byte array to a hexadecimal string.    'PrivateFunction ByteToHex(byteArray AsByte()) AsStringDim outString AsString = ""ForEach b AsByteIn byteArray
        outString &= b.ToString("X2")
      NextReturn outString
    EndFunction

    '    ' HexToByte    '    Converts a hexadecimal string to a byte array.    'PrivateFunction HexToByte(hexString AsString) AsByte()
      Dim returnBytes() AsByte = NewByte(CInt((hexString.Length / 2) - 1)) {}

      For i AsInteger= 0 To returnBytes.Length - 1
        returnBytes(i) = Convert.ToByte(hexString.Substring(i*2, 2), 16)
      NextReturn returnBytes
    EndFunctionEndClassEndNamespace

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.ProtectedConfiguration
{

  publicclass TripleDESProtectedConfigurationProvider : ProtectedConfigurationProvider
  {

    private TripleDESCryptoServiceProvider des = new TripleDESCryptoServiceProvider();

    privatestring pKeyFilePath;
    privatestring pName;

    publicstring KeyFilePath
    {
      get { return pKeyFilePath; }
    }


    //// ProviderBase.Name//publicoverridestring Name
    {
      get { return pName; }
    }


    //// ProviderBase.Initialize//publicoverridevoid Initialize(string name, NameValueCollection config)
    {
      pName = name;
      pKeyFilePath = config["keyFilePath"];
      ReadKey(KeyFilePath);
    }


    //// ProtectedConfigurationProvider.Encrypt//publicoverride XmlNode Encrypt(XmlNode node)
    {
      string encryptedData = EncryptString(node.OuterXml);

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

      return xmlDoc.DocumentElement;
    }


    //// ProtectedConfigurationProvider.Decrypt//publicoverride XmlNode Decrypt(XmlNode encryptedNode)
    {
      string decryptedData = DecryptString(encryptedNode.InnerText);

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

      return xmlDoc.DocumentElement;
    }


    //// EncryptString//    Encrypts a configuration section and returns the encrypted// XML as a string.//privatestring 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);
    }


    //// DecryptString//    Decrypts an encrypted configuration section and returns the// unencrypted XML as a string.//privatestring 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);
    }

    //// CreateKey//    Generates a new TripleDES key and vector and writes them// to the supplied file path.//publicvoid 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();
    }


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


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

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

      return outString;
    }

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

  }
}

Protected Configuration Provider Implementation Example

Example

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