'-----------------------------------------------------------------------
'  This file is part of the Microsoft .NET Framework SDK Code Samples.
' 
'  Copyright (C) Microsoft Corporation.  All rights reserved.
' 
'This source code is intended only as a supplement to Microsoft
'Development Tools and/or on-line documentation.  See these other
'materials for detailed information regarding Microsoft code samples.
' 
'THIS CODE AND INFORMATION ARE PROVIDED AS IS WITHOUT WARRANTY OF ANY
'KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
'IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
'PARTICULAR PURPOSE.
'-----------------------------------------------------------------------
Imports System.IO
Imports System.Security.Cryptography
Imports System.Text

Namespace Microsoft.Samples.Cryptography.FileEncryptVB

    Class FileEncrypt
        Public Shared Function ConvertStringToByteArray(ByVal s As [String]) As [Byte]()
            Return (New UnicodeEncoding).GetBytes(s)
        End Function 'ConvertStringToByteArray


        Public Shared Sub Main()
            Dim fs As New FileStream("EncryptedFile.txt", FileMode.Create, FileAccess.Write)

            'Creating a file stream

            Console.WriteLine("Enter Some Text to be stored in encrypted file:")
            Dim strinput As [String] = Console.ReadLine()
            Dim bytearrayinput As [Byte]() = ConvertStringToByteArray(strinput)
            'DES instance with random key
            Dim des As New DESCryptoServiceProvider
            'create DES Encryptor from this instance
            Dim desencrypt As ICryptoTransform = des.CreateEncryptor()
            'Create Crypto Stream that transforms file stream using des encryption
            Dim cryptostream As New CryptoStream(fs, desencrypt, CryptoStreamMode.Write)
            'write out DES encrypted file
            cryptostream.Write(bytearrayinput, 0, bytearrayinput.Length)

            cryptostream.Close()
            'create file stream to read encrypted file back
            Dim fsread As New FileStream("EncryptedFile.txt", FileMode.Open, FileAccess.Read)
            'create DES Decryptor from our des instance
            Dim desdecrypt As ICryptoTransform = des.CreateDecryptor()
            'create crypto stream set to read and do a des decryption transform on incoming bytes
            Dim cryptostreamDecr As New CryptoStream(fsread, desdecrypt, CryptoStreamMode.Read)
            'print out the contents of the decrypted file
            Console.WriteLine(New StreamReader(cryptostreamDecr, New UnicodeEncoding).ReadToEnd())

            Console.WriteLine()
            Console.WriteLine("Press Enter to continue...")
            Console.ReadLine()
        End Sub 'Main
    End Class 'FileEncrypt
End Namespace