' This sample demonstrates using a key based on the cryptographic service provider (CSP) version
' of the Data Encryption Standard (DES)algorithm to encrypt a string to a byte array, and then 
' to decrypt the byte array back to a string.
Imports System
Imports System.IO
Imports System.Text
Imports System.Security.Cryptography



Class CryptoMemoryStream

    ' Main method.
    Public Shared Sub Main()
        ' Create a new DES key.
        Dim key As New DESCryptoServiceProvider()

        ' Encrypt a string to a byte array.
        Dim buffer As Byte() = Encrypt("This is some plaintext!", key)

        ' Decrypt the byte array back to a string.
        Dim plaintext As String = Decrypt(buffer, key)

        ' Display the plaintext value to the console.
        Console.WriteLine(plaintext)
    End Sub 'Main


    ' Encrypt the string.
    Public Shared Function Encrypt(PlainText As String, key As SymmetricAlgorithm) As Byte()
        ' Create a memory stream.
        Dim ms As New MemoryStream()

        ' Create a CryptoStream using the memory stream and the 
        ' CSP DES key.  
        Dim encStream As New CryptoStream(ms, key.CreateEncryptor(), CryptoStreamMode.Write)

        ' Create a StreamWriter to write a string
        ' to the stream.
        Dim sw As New StreamWriter(encStream)

        ' Write the plaintext to the stream.
        sw.WriteLine(PlainText)

        ' Close the StreamWriter and CryptoStream.
        sw.Close()
        encStream.Close()

        ' Get an array of bytes that represents
        ' the memory stream.
        Dim buffer As Byte() = ms.ToArray()

        ' Close the memory stream.
        ms.Close()

        ' Return the encrypted byte array.
        Return buffer
    End Function 'Encrypt


    ' Decrypt the byte array.
    Public Shared Function Decrypt(CypherText() As Byte, key As SymmetricAlgorithm) As String
        ' Create a memory stream to the passed buffer.
        Dim ms As New MemoryStream(CypherText)

        ' Create a CryptoStream using the memory stream and the 
        ' CSP DES key. 
        Dim encStream As New CryptoStream(ms, key.CreateDecryptor(), CryptoStreamMode.Read)

        ' Create a StreamReader for reading the stream.
        Dim sr As New StreamReader(encStream)

        ' Read the stream as a string.
        Dim val As String = sr.ReadLine()

        ' Close the streams.
        sr.Close()
        encStream.Close()
        ms.Close()

        Return val
    End Function 'Decrypt
End Class 'CryptoMemoryStream

// This sample demonstrates using a key based on the cryptographic service provider (CSP) version
// of the Data Encryption Standard (DES)algorithm to encrypt a string to a byte array, and then 
// to decrypt the byte array back to a string.

using System;
using System.IO;
using System.Text;
using System.Security.Cryptography;

class CryptoMemoryStream
{
    // Main method.
    public static void Main()
    {
        // Create a new DES key.
        DESCryptoServiceProvider key = new DESCryptoServiceProvider();

        // Encrypt a string to a byte array.
        byte[] buffer = Encrypt("This is some plaintext!", key);

        // Decrypt the byte array back to a string.
        string plaintext =  Decrypt(buffer, key);

        // Display the plaintext value to the console.
        Console.WriteLine(plaintext);
    }

    // Encrypt the string.
    public static byte[] Encrypt(string PlainText, SymmetricAlgorithm key)
    {
        // Create a memory stream.
        MemoryStream ms = new MemoryStream();

        // Create a CryptoStream using the memory stream and the 
        // CSP DES key.  
        CryptoStream encStream = new CryptoStream(ms, key.CreateEncryptor(), CryptoStreamMode.Write);

        // Create a StreamWriter to write a string
        // to the stream.
        StreamWriter sw = new StreamWriter(encStream);

        // Write the plaintext to the stream.
        sw.WriteLine(PlainText);

        // Close the StreamWriter and CryptoStream.
        sw.Close();
        encStream.Close();

        // Get an array of bytes that represents
        // the memory stream.
        byte[] buffer = ms.ToArray();

        // Close the memory stream.
        ms.Close();

        // Return the encrypted byte array.
        return buffer;
    }

   // Decrypt the byte array.
    public static string Decrypt(byte[] CypherText, SymmetricAlgorithm key)
    {
        // Create a memory stream to the passed buffer.
        MemoryStream ms = new MemoryStream(CypherText);

        // Create a CryptoStream using the memory stream and the 
        // CSP DES key. 
        CryptoStream encStream = new CryptoStream(ms, key.CreateDecryptor(), CryptoStreamMode.Read);

        // Create a StreamReader for reading the stream.
        StreamReader sr = new StreamReader(encStream);

        // Read the stream as a string.
        string val = sr.ReadLine();

        // Close the streams.
        sr.Close();
        encStream.Close();
        ms.Close();

        return val;
    }
}

// This sample demonstrates using a key based on the cryptographic service provider (CSP) version
// of the Data Encryption Standard (DES)algorithm to encrypt a string to a byte array, and then 
// to decrypt the byte array back to a string.
using namespace System;
using namespace System::IO;
using namespace System::Text;
using namespace System::Security::Cryptography;

// Encrypt the string.
array<Byte>^ Encrypt( String^ PlainText, SymmetricAlgorithm^ key )
{

   // Create a memory stream.
   MemoryStream^ ms = gcnew MemoryStream;

   // Create a CryptoStream using the memory stream and the 
   // CSP DES key.  
   CryptoStream^ encStream = gcnew CryptoStream( ms,key->CreateEncryptor(),CryptoStreamMode::Write );

   // Create a StreamWriter to write a string
   // to the stream.
   StreamWriter^ sw = gcnew StreamWriter( encStream );

   // Write the plaintext to the stream.
   sw->WriteLine( PlainText );

   // Close the StreamWriter and CryptoStream.
   sw->Close();
   encStream->Close();

   // Get an array of bytes that represents
   // the memory stream.
   array<Byte>^buffer = ms->ToArray();

   // Close the memory stream.
   ms->Close();

   // Return the encrypted byte array.
   return buffer;
}


// Decrypt the byte array.
String^ Decrypt( array<Byte>^CypherText, SymmetricAlgorithm^ key )
{

   // Create a memory stream to the passed buffer.
   MemoryStream^ ms = gcnew MemoryStream( CypherText );

   // Create a CryptoStream using the memory stream and the 
   // CSP DES key. 
   CryptoStream^ encStream = gcnew CryptoStream( ms,key->CreateDecryptor(),CryptoStreamMode::Read );

   // Create a StreamReader for reading the stream.
   StreamReader^ sr = gcnew StreamReader( encStream );

   // Read the stream as a string.
   String^ val = sr->ReadLine();

   // Close the streams.
   sr->Close();
   encStream->Close();
   ms->Close();
   return val;
}

int main()
{

   // Create a new DES key.
   DESCryptoServiceProvider^ key = gcnew DESCryptoServiceProvider;

   // Encrypt a string to a byte array.
   array<Byte>^buffer = Encrypt( "This is some plaintext!", key );

   // Decrypt the byte array back to a string.
   String^ plaintext = Decrypt( buffer, key );

   // Display the plaintext value to the console.
   Console::WriteLine( plaintext );
}