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TripleDESCryptoServiceProvider Class

Updated: March 2012

Defines a wrapper object to access the cryptographic service provider (CSP) version of the TripleDES algorithm. This class cannot be inherited.

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

[ComVisibleAttribute(true)]
public ref class TripleDESCryptoServiceProvider sealed : public TripleDES

This algorithm supports key lengths from 128 bits to 192 bits in increments of 64 bits.

NoteNote:

A newer symmetric encryption algorithm, Advanced Encryption Standard (AES), is available. Consider using the AesCryptoServiceProvider class instead of the TripleDESCryptoServiceProvider class.

The following code example creates a TripleDESCryptoServiceProvider object and uses it to encrypt and decrypt data in a file.

using namespace System;
using namespace System::Security::Cryptography;
using namespace System::Text;
using namespace System::IO;
void EncryptTextToFile( String^ Data, String^ FileName, array<Byte>^Key, array<Byte>^IV )
{
   try
   {

      // Create or open the specified file.
      FileStream^ fStream = File::Open( FileName, FileMode::OpenOrCreate );

      // Create a CryptoStream using the FileStream  
      // and the passed key and initialization vector (IV).
      CryptoStream^ cStream = gcnew CryptoStream( fStream,(gcnew TripleDESCryptoServiceProvider)->CreateEncryptor( Key, IV ),CryptoStreamMode::Write );

      // Create a StreamWriter using the CryptoStream.
      StreamWriter^ sWriter = gcnew StreamWriter( cStream );

      // Write the data to the stream  
      // to encrypt it.
      sWriter->WriteLine( Data );

      // Close the streams and 
      // close the file.
      sWriter->Close();
      cStream->Close();
      fStream->Close();
   }
   catch ( CryptographicException^ e ) 
   {
      Console::WriteLine( "A Cryptographic error occurred: {0}", e->Message );
   }
   catch ( UnauthorizedAccessException^ e ) 
   {
      Console::WriteLine( "A file access error occurred: {0}", e->Message );
   }

}

String^ DecryptTextFromFile( String^ FileName, array<Byte>^Key, array<Byte>^IV )
{
   try
   {

      // Create or open the specified file. 
      FileStream^ fStream = File::Open( FileName, FileMode::OpenOrCreate );

      // Create a CryptoStream using the FileStream  
      // and the passed key and initialization vector (IV).
      CryptoStream^ cStream = gcnew CryptoStream( fStream,(gcnew TripleDESCryptoServiceProvider)->CreateDecryptor( Key, IV ),CryptoStreamMode::Read );

      // Create a StreamReader using the CryptoStream.
      StreamReader^ sReader = gcnew StreamReader( cStream );

      // Read the data from the stream  
      // to decrypt it.
      String^ val = sReader->ReadLine();

      // Close the streams and 
      // close the file.
      sReader->Close();
      cStream->Close();
      fStream->Close();

      // Return the string.  
      return val;
   }
   catch ( CryptographicException^ e ) 
   {
      Console::WriteLine( "A Cryptographic error occurred: {0}", e->Message );
      return nullptr;
   }
   catch ( UnauthorizedAccessException^ e ) 
   {
      Console::WriteLine( "A file access error occurred: {0}", e->Message );
      return nullptr;
   }

}

int main()
{
   try
   {

      // Create a new TripleDESCryptoServiceProvider object 
      // to generate a key and initialization vector (IV).
      TripleDESCryptoServiceProvider^ tDESalg = gcnew TripleDESCryptoServiceProvider;

      // Create a string to encrypt.
      String^ sData = "Here is some data to encrypt.";
      String^ FileName = "CText.txt";

      // Encrypt text to a file using the file name, key, and IV.
      EncryptTextToFile( sData, FileName, tDESalg->Key, tDESalg->IV );

      // Decrypt the text from a file using the file name, key, and IV.
      String^ Final = DecryptTextFromFile( FileName, tDESalg->Key, tDESalg->IV );

      // Display the decrypted string to the console.
      Console::WriteLine( Final );
   }
   catch ( Exception^ e ) 
   {
      Console::WriteLine( e->Message );
   }

}

The following code example creates a TripleDESCryptoServiceProvider object and uses it to encrypt and decrypt data in memory.

using namespace System;
using namespace System::Security::Cryptography;
using namespace System::Text;
using namespace System::IO;
array<Byte>^ EncryptTextToMemory( String^ Data, array<Byte>^Key, array<Byte>^IV )
{
   try
   {

      // Create a MemoryStream.
      MemoryStream^ mStream = gcnew MemoryStream;

      // Create a CryptoStream using the MemoryStream  
      // and the passed key and initialization vector (IV).
      CryptoStream^ cStream = gcnew CryptoStream( mStream,(gcnew TripleDESCryptoServiceProvider)->CreateEncryptor( Key, IV ),CryptoStreamMode::Write );

      // Convert the passed string to a byte array. 
      array<Byte>^toEncrypt = (gcnew ASCIIEncoding)->GetBytes( Data );

      // Write the byte array to the crypto stream and flush it.
      cStream->Write( toEncrypt, 0, toEncrypt->Length );
      cStream->FlushFinalBlock();

      // Get an array of bytes from the  
      // MemoryStream that holds the  
      // encrypted data. 
      array<Byte>^ret = mStream->ToArray();

      // Close the streams.
      cStream->Close();
      mStream->Close();

      // Return the encrypted buffer. 
      return ret;
   }
   catch ( CryptographicException^ e ) 
   {
      Console::WriteLine( "A Cryptographic error occurred: {0}", e->Message );
      return nullptr;
   }

}

String^ DecryptTextFromMemory( array<Byte>^Data, array<Byte>^Key, array<Byte>^IV )
{
   try
   {

      // Create a new MemoryStream using the passed  
      // array of encrypted data.
      MemoryStream^ msDecrypt = gcnew MemoryStream( Data );

      // Create a CryptoStream using the MemoryStream  
      // and the passed key and initialization vector (IV).
      CryptoStream^ csDecrypt = gcnew CryptoStream( msDecrypt,(gcnew TripleDESCryptoServiceProvider)->CreateDecryptor( Key, IV ),CryptoStreamMode::Read );

      // Create buffer to hold the decrypted data. 
      array<Byte>^fromEncrypt = gcnew array<Byte>(Data->Length);

      // Read the decrypted data out of the crypto stream 
      // and place it into the temporary buffer.
      csDecrypt->Read( fromEncrypt, 0, fromEncrypt->Length );

      //Convert the buffer into a string and return it. 
      return (gcnew ASCIIEncoding)->GetString( fromEncrypt );
   }
   catch ( CryptographicException^ e ) 
   {
      Console::WriteLine( "A Cryptographic error occurred: {0}", e->Message );
      return nullptr;
   }

}

int main()
{
   try
   {

      // Create a new TripleDESCryptoServiceProvider object 
      // to generate a key and initialization vector (IV).
      TripleDESCryptoServiceProvider^ tDESalg = gcnew TripleDESCryptoServiceProvider;

      // Create a string to encrypt.
      String^ sData = "Here is some data to encrypt.";

      // Encrypt the string to an in-memory buffer. 
      array<Byte>^Data = EncryptTextToMemory( sData, tDESalg->Key, tDESalg->IV );

      // Decrypt the buffer back to a string.
      String^ Final = DecryptTextFromMemory( Data, tDESalg->Key, tDESalg->IV );

      // Display the decrypted string to the console.
      Console::WriteLine( Final );
   }
   catch ( Exception^ e ) 
   {
      Console::WriteLine( e->Message );
   }

}

System::Object
  System.Security.Cryptography::SymmetricAlgorithm
    System.Security.Cryptography::TripleDES
      System.Security.Cryptography::TripleDESCryptoServiceProvider

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 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC

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

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0

Date

History

Reason

March 2012

Updated Visual Basic example.

Customer feedback.

February 2009

Added note about newer AES algorithm.

Information enhancement.

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