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TripleDESCryptoServiceProvider Class

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)

'Declaration
<ComVisibleAttribute(True)> _
Public NotInheritable Class TripleDESCryptoServiceProvider
	Inherits TripleDES
'Usage
Dim instance As TripleDESCryptoServiceProvider

/** @attribute ComVisibleAttribute(true) */ 
public final class TripleDESCryptoServiceProvider extends TripleDES
ComVisibleAttribute(true) 
public final class TripleDESCryptoServiceProvider extends TripleDES

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

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

Imports System.Security.Cryptography
Imports System.Text
Imports System.IO

Module TrippleDESCSPSample

    Sub Main()
        Try
            ' Create a new TripleDESCryptoServiceProvider object
            ' to generate a key and initialization vector (IV).
            Dim tDESalg As New TripleDESCryptoServiceProvider

            ' Create a string to encrypt.
            Dim sData As String = "Here is some data to encrypt."
            Dim FileName As String = "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.
            Dim Final As String = DecryptTextFromFile(FileName, tDESalg.Key, tDESalg.IV)

            ' Display the decrypted string to the console.
            Console.WriteLine(Final)
        Catch e As Exception
            Console.WriteLine(e.Message)
        End Try
    End Sub


    Sub EncryptTextToFile(ByVal Data As String, ByVal FileName As String, ByVal Key() As Byte, ByVal IV() As Byte)
        Try
            ' Create or open the specified file.
            Dim fStream As FileStream = File.Open(FileName, FileMode.OpenOrCreate)

            ' Create a CryptoStream using the FileStream 
            ' and the passed key and initialization vector (IV).
            Dim cStream As New CryptoStream(fStream, _
                                            New TripleDESCryptoServiceProvider().CreateEncryptor(Key, IV), _
                                            CryptoStreamMode.Write)

            ' Create a StreamWriter using the CryptoStream.
            Dim sWriter As New 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 e As CryptographicException
            Console.WriteLine("A Cryptographic error occurred: {0}", e.Message)
        Catch e As UnauthorizedAccessException
            Console.WriteLine("A file error occurred: {0}", e.Message)
        End Try
    End Sub


    Function DecryptTextFromFile(ByVal FileName As String, ByVal Key() As Byte, ByVal IV() As Byte) As String
        Try
            ' Create or open the specified file. 
            Dim fStream As FileStream = File.Open(FileName, FileMode.OpenOrCreate)

            ' Create a CryptoStream using the FileStream 
            ' and the passed key and initialization vector (IV).
            Dim cStream As New CryptoStream(fStream, _
                                            New TripleDESCryptoServiceProvider().CreateDecryptor(Key, IV), _
                                            CryptoStreamMode.Read)

            ' Create a StreamReader using the CryptoStream.
            Dim sReader As New StreamReader(cStream)

            ' Read the data from the stream 
            ' to decrypt it.
            Dim val As String = sReader.ReadLine()

            ' Close the streams and
            ' close the file.
            sReader.Close()
            cStream.Close()
            fStream.Close()

            ' Return the string. 
            Return val
        Catch e As CryptographicException
            Console.WriteLine("A Cryptographic error occurred: {0}", e.Message)
            Return Nothing
        Catch e As UnauthorizedAccessException
            Console.WriteLine("A file error occurred: {0}", e.Message)
            Return Nothing
        End Try
    End Function
End Module

import System.*;
import System.Security.Cryptography.*;
import System.Text.*;
import System.IO.*;

class TrippleDESCSPSample
{
    public static void main(String[] args)
    {
        try {
            // Create a new TripleDESCryptoServiceProvider object
            // to generate a key and initialization vector (iv).
            TripleDESCryptoServiceProvider tDESalg = 
                new 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.get_Key(), 
                tDESalg.get_IV());

            // Decrypt the text from a file using the file name, key, and iv.
            String strFinal = DecryptTextFromFile(fileName, tDESalg.get_Key(), 
                tDESalg.get_IV());

            // Display the decrypted string to the console.
            Console.WriteLine(strFinal);
        }
        catch (System.Exception e) {
            Console.WriteLine(e.get_Message());
        }
    } //main

    public static void EncryptTextToFile(String data, String fileName, 
        ubyte key[], ubyte 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 = new CryptoStream(fStream, 
                (new TripleDESCryptoServiceProvider()).CreateEncryptor(key, 
                iv), CryptoStreamMode.Write);

            // Create a StreamWriter using the CryptoStream.
            StreamWriter sWriter = new 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.get_Message());
        }
        catch (UnauthorizedAccessException e) {
            Console.WriteLine("A file access error occurred: {0}", 
                e.get_Message());
        }
    } //EncryptTextToFile

    public static String DecryptTextFromFile(String fileName, ubyte key[], 
        ubyte 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 = new CryptoStream(fStream, 
                (new TripleDESCryptoServiceProvider()).CreateDecryptor(key, iv), 
                CryptoStreamMode.Read);

            // Create a StreamReader using the CryptoStream.
            StreamReader sReader = new 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.get_Message());
            return null;
        }
        catch (UnauthorizedAccessException e) {
            Console.WriteLine("A file access error occurred: {0}", 
                e.get_Message());
            return null;
        }
    } //DecryptTextFromFile
} //TrippleDESCSPSample

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

Imports System.Security.Cryptography
Imports System.Text
Imports System.IO

Module TrippleDESCSPSample

    Sub Main()
        Try
            ' Create a new TripleDESCryptoServiceProvider object
            ' to generate a key and initialization vector (IV).
            Dim tDESalg As New TripleDESCryptoServiceProvider

            ' Create a string to encrypt.
            Dim sData As String = "Here is some data to encrypt."

            ' Encrypt the string to an in-memory buffer.
            Dim Data As Byte() = EncryptTextToMemory(sData, tDESalg.Key, tDESalg.IV)

            ' Decrypt the buffer back to a string.
            Dim Final As String = DecryptTextFromMemory(Data, tDESalg.Key, tDESalg.IV)

            ' Display the decrypted string to the console.
            Console.WriteLine(Final)
        Catch e As Exception
            Console.WriteLine(e.Message)
        End Try
    End Sub


    Function EncryptTextToMemory(ByVal Data As String, ByVal Key() As Byte, ByVal IV() As Byte) As Byte()
        Try
            ' Create a MemoryStream.
            Dim mStream As New MemoryStream

            ' Create a CryptoStream using the MemoryStream 
            ' and the passed key and initialization vector (IV).
            Dim cStream As New CryptoStream(mStream, _
                                            New TripleDESCryptoServiceProvider().CreateEncryptor(Key, IV), _
                                            CryptoStreamMode.Write)

            ' Convert the passed string to a byte array.
            Dim toEncrypt As Byte() = New 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.
            Dim ret As Byte() = mStream.ToArray()

            ' Close the streams.
            cStream.Close()
            mStream.Close()

            ' Return the encrypted buffer.
            Return ret
        Catch e As CryptographicException
            Console.WriteLine("A Cryptographic error occurred: {0}", e.Message)
            Return Nothing
        End Try
    End Function


    Function DecryptTextFromMemory(ByVal Data() As Byte, ByVal Key() As Byte, ByVal IV() As Byte) As String
        Try
            ' Create a new MemoryStream using the passed 
            ' array of encrypted data.
            Dim msDecrypt As New MemoryStream(Data)

            ' Create a CryptoStream using the MemoryStream 
            ' and the passed key and initialization vector (IV).
            Dim csDecrypt As New CryptoStream(msDecrypt, _
                                              New TripleDESCryptoServiceProvider().CreateDecryptor(Key, IV), _
                                              CryptoStreamMode.Read)

            ' Create buffer to hold the decrypted data.
            Dim fromEncrypt(Data.Length) As Byte

            ' 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 New ASCIIEncoding().GetString(fromEncrypt)
        Catch e As CryptographicException
            Console.WriteLine("A Cryptographic error occurred: {0}", e.Message)
            Return Nothing
        End Try
    End Function
End Module

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 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, 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, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0

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