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ProtectedData Class

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

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

'Declaration
Public NotInheritable Class ProtectedData
'Usage
Dim instance As ProtectedData

public final class ProtectedData
public final class ProtectedData
Not applicable.

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.

Imports System
Imports System.Security.Cryptography



Public Class DataProtectionSample
    ' Create byte array for additional entropy when using Protect method.
    Private Shared s_aditionalEntropy As Byte() = {9, 8, 7, 6, 5}


    Public Shared Sub Main()
        ' Create a simple byte array containing data to be encrypted.
        Dim secret As Byte() = {0, 1, 2, 3, 4, 1, 2, 3, 4}

        'Encrypt the data.
        Dim encryptedSecret As Byte() = Protect(secret)
        Console.WriteLine("The encrypted byte array is:")
        PrintValues(encryptedSecret)

        ' Decrypt the data and store in a byte array.
        Dim originalData As Byte() = Unprotect(encryptedSecret)
        Console.WriteLine("{0}The original data is:", Environment.NewLine)
        PrintValues(originalData)

    End Sub


    Public Shared Function Protect(ByVal data() As Byte) As Byte()
        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 e As CryptographicException
            Console.WriteLine("Data was not encrypted. An error occurred.")
            Console.WriteLine(e.ToString())
            Return Nothing
        End Try

    End Function


    Public Shared Function Unprotect(ByVal data() As Byte) As Byte()
        Try
            'Decrypt the data using DataProtectionScope.CurrentUser.
            Return ProtectedData.Unprotect(data, s_aditionalEntropy, DataProtectionScope.CurrentUser)
        Catch e As CryptographicException
            Console.WriteLine("Data was not decrypted. An error occurred.")
            Console.WriteLine(e.ToString())
            Return Nothing
        End Try

    End Function


    Public Shared Sub PrintValues(ByVal myArr() As [Byte])
        Dim i As [Byte]
        For Each i In myArr
            Console.Write(vbTab + "{0}", i)
        Next i
        Console.WriteLine()

    End Sub
End Class

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

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0
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