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ProtectedData Class

Note: This class is new in the .NET Framework version 2.0.

Provides methods for protecting and unprotecting data. This class cannot be inherited.

Namespace: System.Security.Cryptography
Assembly: System.Security (in system.security.dll)

public sealed class ProtectedData
public final class ProtectedData
public final class ProtectedData

This class provides access to the Data Protection API (DPAPI) available in Microsoft Windows 2000 and later operating systems. This is a service that is provided by the operating system and does not require additional libraries. It provides protection using the user or machine credentials to protect or unprotect data.

The class consists of two wrappers for the unmanaged DPAPI, Protect and Unprotect. These two methods can be used to protect and unprotect data such as passwords, keys, and connection strings.

TopicLocation
How to: Use Data Protection.NET Framework: Security
How to: Use Data Protection.NET Framework: Security

The following code example shows how to use data protection.

using System;
using System.Security.Cryptography;

public class DataProtectionSample
{
// Create byte array for additional entropy when using Protect method.
	static byte [] s_aditionalEntropy = { 9, 8, 7, 6, 5 };

	public static void Main()
	{
// Create a simple byte array containing data to be encrypted.
		
byte [] secret = { 0, 1, 2, 3, 4, 1, 2, 3, 4 };

//Encrypt the data.
		byte [] encryptedSecret = Protect( secret );
		Console.WriteLine("The encrypted byte array is:");
		PrintValues(encryptedSecret);
		
// Decrypt the data and store in a byte array.
		byte [] originalData = Unprotect( encryptedSecret );
		Console.WriteLine("{0}The original data is:", Environment.NewLine);
		PrintValues(originalData);

	}

	public static byte [] Protect( byte [] data )
	{
		try
		{
			// Encrypt the data using DataProtectionScope.CurrentUser. The result can be decrypted
			//  only by the same current user.
			return ProtectedData.Protect( data, s_aditionalEntropy, DataProtectionScope.CurrentUser );
		} 
		catch (CryptographicException e)
		{
			Console.WriteLine("Data was not encrypted. An error occurred.");
			Console.WriteLine(e.ToString());
			return null;
		}
	}

	public static byte [] Unprotect( byte [] data )
	{
		try
		{
			//Decrypt the data using DataProtectionScope.CurrentUser.
			return ProtectedData.Unprotect( data, s_aditionalEntropy, DataProtectionScope.CurrentUser );
		} 
		catch (CryptographicException e)
		{
			Console.WriteLine("Data was not decrypted. An error occurred.");
			Console.WriteLine(e.ToString());
			return null;
		}
	}

	public static void PrintValues( Byte[] myArr )  
	{
	      foreach ( Byte i in myArr )  
		  	{
		         Console.Write( "\t{0}", i );
			 }
      Console.WriteLine();
	 }

}

import System.*;
import System.Security.Cryptography.*;

public class DataProtectionSample
{
    // Create byte array for additional entropy when using Protect method.
    private static ubyte sAditionalEntropy[] =  { 9, 8, 7, 6, 5 };

    public static void main(String args[])
    {
        // Create a simple byte array containing data to be encrypted.
        ubyte secret[] =  { 0, 1, 2, 3, 4, 1, 2, 3, 4 };
        //Encrypt the data.
        ubyte encryptedSecret[] = Protect(secret);
        Console.WriteLine("The encrypted byte array is:");
        PrintValues(encryptedSecret);
        // Decrypt the data and store in a byte array.
        ubyte originalData[] = Unprotect(encryptedSecret);
        Console.WriteLine("{0}The original data is:", 
            Environment.get_NewLine());
        PrintValues(originalData);
    } //main

    public static ubyte[] Protect(ubyte data[])
    {
        try {
            // Encrypt the data using DataProtectionScope.CurrentUser. 
            // The result can be decrypted only by the same current user.
            return ProtectedData.Protect(data, sAditionalEntropy, 
                DataProtectionScope.CurrentUser);
        }
        catch (CryptographicException e) {
            Console.WriteLine("Data was not encrypted. An error occurred.");
            Console.WriteLine(e.ToString());
            return null;
        }
    } //Protect

    public static ubyte[] Unprotect(ubyte data[])
    {
        try {
            //Decrypt the data using DataProtectionScope.CurrentUser.
            return ProtectedData.Unprotect(data, sAditionalEntropy, 
                DataProtectionScope.CurrentUser);
        }
        catch (CryptographicException e) {
            Console.WriteLine("Data was not decrypted. An error occurred.");
            Console.WriteLine(e.ToString());
            return null;
        }
    } //Unprotect

    public static void PrintValues(ubyte myArr[])
    {
        for (int iCtr = 0; iCtr < myArr.length; iCtr++) {
            ubyte i = myArr[iCtr];
            Console.Write("\t{0}", System.Convert.ToString(i));
        }
        Console.WriteLine();
    } //PrintValues
} //DataProtectionSample 

System.Object
  System.Security.Cryptography.ProtectedData

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 2000 SP4, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0

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