ProtectedData::Protect Method (array<Byte>^, array<Byte>^, DataProtectionScope)

.NET Framework (current version)

Encrypts the data in a specified byte array and returns a byte array that contains the encrypted data.

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

Syntax

public:
static array<unsigned char>^ Protect(
	array<unsigned char>^ userData,
	array<unsigned char>^ optionalEntropy,
	DataProtectionScope scope
)

Parameters

userData: Type: array<System::Byte>^
A byte array that contains data to encrypt.

optionalEntropy: Type: array<System::Byte>^
An optional additional byte array used to increase the complexity of the encryption, or null for no additional complexity.

scope: Type: System.Security.Cryptography::DataProtectionScope
One of the enumeration values that specifies the scope of encryption.

Return Value

Type: array<System::Byte>^

A byte array representing the encrypted data.

Exceptions

Exception	Condition
ArgumentNullException	The userData parameter is null.
CryptographicException	The encryption failed.
NotSupportedException	The operating system does not support this method.
OutOfMemoryException	The system ran out of memory while encrypting the data.

This method can be used to encrypt data such as passwords, keys, or connection strings. The optionalEntropy parameter enables you to add data to increase the complexity of the encryption; specify null for no additional complexity. If provided, this information must also be used when decrypting the data using the Unprotect method.

Note
If you use this method during impersonation, you may receive the following error: "Key not valid for use in specified state." To prevent this error, load the profile of the user you want to impersonate before calling the method.

Examples

The following example shows how to use data protection.

C++

#using <System.Security.dll>

using namespace System;
using namespace System::Security::Cryptography;

public ref class DataProtectionSample
{
private:

   // Create byte array for additional entropy when using Protect method.
   static array<Byte>^s_aditionalEntropy = {9,8,7,6,5};

public:
   static void Main()
   {

      // Create a simple byte array containing data to be encrypted.
      array<Byte>^secret = {0,1,2,3,4,1,2,3,4};

      //Encrypt the data.
      array<Byte>^encryptedSecret = Protect( secret );
      Console::WriteLine( "The encrypted byte array is:" );
      PrintValues( encryptedSecret );

      // Decrypt the data and store in a byte array.
      array<Byte>^originalData = Unprotect( encryptedSecret );
      Console::WriteLine( "{0}The original data is:", Environment::NewLine );
      PrintValues( originalData );
   }

   static array<Byte>^ Protect( array<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 );
         return nullptr;
      }
   }

   static array<Byte>^ Unprotect( array<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 );
         return nullptr;
      }
   }

   static void PrintValues( array<Byte>^myArr )
   {
      System::Collections::IEnumerator^ myEnum = myArr->GetEnumerator();
      while ( myEnum->MoveNext() )
      {
         Byte i = safe_cast<Byte>(myEnum->Current);
         Console::Write( "\t{0}", i );
      }

      Console::WriteLine();
   }
};

int main()
{
   DataProtectionSample::Main();
}

Security

DataProtectionPermission

with the associated ProtectData flag for permission to protect data.

Version Information

.NET Framework
Available since 2.0