ProtectedData Class
Assembly: System.Security (in system.security.dll)
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.
| Topic | Location |
|---|---|
| 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