Keskustelu: Koodit: VB.NET: DES-salaus

'salaa tiedosto random avaimella ja tallentaa avaimen salattuna avain tiedostoon
Dim inName As String 'salattava tiedosto
Dim outName As String 'salattutiedosto
Dim avattuName As String 'salattutiedosto
Dim avaimetName As String ' avainten tiedosto salattuna
Dim desKey(23) As Byte 'avain 24=3*8 tavua
Dim desIV(7) As Byte ' aloitusvektori 8 tavua
Dim i As Integer
Dim password As String
TextBox1.Text = ""

Dim rng As New RNGCryptoServiceProvider 'random number generator
'valitaan jokin salausavain
rng.GetBytes(desKey)
'valitaan jokin aloitusvektori
rng.GetBytes(desIV)
password = InputBox("Anna salasana", "SALAKIRJOITETAAN", "salasanaXYZ8")


'tidostonimet
inName = "C:\test.txt"
outName = "C:\salattu_test.des"
avattuName = "C:\test_avattu.txt"
avaimetName = "C:\DESavaimet.bin" 'avaimet tallessa salattuna salasanalla password

'luokka FileCrypt on SHARED =>> ei tarvitse tehdä instanssia
'salataan
FileCrypt.EncryptData(inName, outName, desKey, desIV)
FileCrypt.SaveKeyToFile(desKey, desIV, avaimetName, password) 'avaimet talteen
TextBox1.Text = "Salaus tehty"
'avataan salaus
password = ""
password = InputBox("Anna salasana", "AVATAAN SALAKIRJOITUS", "salasanaXYZ8")
FileCrypt.OpenKeyFromFile(desKey, desIV, avaimetName, password)
FileCrypt.DecryptData(outName, avattuName, desKey, desIV)
TextBox1.Text = "Salaus ja avaus tehty"

Imports System
Imports System.IO
Imports System.Xml
Imports System.Text
Imports System.Security.Cryptography
Public Class FileCrypt
    'tiedoston  salakirjoitus TripleDES menetelmällä 3*56 bittiä
    Public Shared Sub EncryptData(ByVal inName As String, ByVal outName As String, _
    ByVal desKey() As Byte, ByVal desIV() As Byte)

        'Create the file streams to handle the input and output files.
        Dim fin As New FileStream(inName, FileMode.Open, FileAccess.Read)
        Dim fout As New FileStream(outName, FileMode.OpenOrCreate, _
           FileAccess.Write)
        fout.SetLength(0)

        'Create variables to help with read and write.
        Dim bin(4096) As Byte 'This is intermediate storage for the encryption.
        Dim rdlen As Long = 0 'This is the total number of bytes written.
        Dim totlen As Long = fin.Length 'Total length of the input file.
        Dim len As Integer 'This is the number of bytes to be written at a time.
        Dim tdes As New TripleDESCryptoServiceProvider
        Dim encStream As New CryptoStream(fout, _
           tdes.CreateEncryptor(desKey, desIV), CryptoStreamMode.Write)

        'Read from the input file, then encrypt and write to the output file.
        While rdlen < totlen
            len = fin.Read(bin, 0, 4096)
            encStream.Write(bin, 0, len)
            rdlen = Convert.ToInt32(rdlen + len / tdes.BlockSize * tdes.BlockSize)
        End While

        encStream.Close()
        fout.Close()
        fin.Close()
    End Sub
    Public Shared Sub DecryptData(ByVal inName As String, ByVal outName As String, _
   ByVal desKey() As Byte, ByVal desIV() As Byte)

        'Create the file streams to handle the input and output files.
        Dim fin As New FileStream(inName, FileMode.Open, FileAccess.Read)
        Dim fout As New FileStream(outName, FileMode.OpenOrCreate, _
           FileAccess.Write)
        fout.SetLength(0)

        'Create variables to help with read and write.
        Dim bin(4096) As Byte 'This is intermediate storage for the encryption.
        Dim rdlen As Long = 0 'This is the total number of bytes written.
        Dim totlen As Long = fin.Length 'Total length of the input file.
        Dim len As Integer 'This is the number of bytes to be written at a time.
        Dim tdes As New TripleDESCryptoServiceProvider
        Dim encStream As New CryptoStream(fout, _
           tdes.CreateDecryptor(desKey, desIV), CryptoStreamMode.Write)

        'Read from the input file, then encrypt and write to the output file.
        While rdlen < totlen
            len = fin.Read(bin, 0, 4096)
            encStream.Write(bin, 0, len)
            rdlen = Convert.ToInt32(rdlen + len / tdes.BlockSize * tdes.BlockSize)
        End While
        Try
            encStream.Close()
        Catch ex As Exception
            MsgBox("EI ONNISTU")   ' Show friendly error message.
        End Try
        fout.Close()
        fin.Close()
    End Sub
    Public Shared Sub SaveKeyToFile(ByVal desKey() As Byte, ByVal desIV() As Byte, ByVal fname As String, ByVal password As String)

        Dim desIV2(8) As Byte
        Dim desKey2(24) As Byte
        'tallentaa avaimet temp tiedostoon
        Dim fout As New FileStream(fname + "_temp", FileMode.OpenOrCreate, FileAccess.Write)
        fout.SetLength(0)
        fout.Write(desKey, 0, 24) 'avain talteen
        fout.Write(desIV, 0, 8) ' aloitusvektori talteen
        fout.Close()
        password = password + password + password + password + password + password + password + password
        password = password.PadRight(32)
        desKey2 = System.Text.Encoding.UTF8.GetBytes(password.Substring(0, 24))
        desIV2 = System.Text.Encoding.UTF8.GetBytes(password.Substring(25))
        'salataan vielä avaimet
        FileCrypt.EncryptData(fname + "_temp", fname, desKey2, desIV2)
        File.Delete(fname + "_temp")
    End Sub
    Public Shared Sub OpenKeyFromFile(ByVal desKey() As Byte, ByVal desIV() As Byte, ByVal fname As String, ByVal password As String)
        Dim desIV2(8) As Byte
        Dim desKey2(24) As Byte
        'pura avainten salakirjoitus
        password = password + password + password + password + password + password + password + password
        password = password.PadRight(32) 'minimipituus
        desKey2 = System.Text.Encoding.UTF8.GetBytes(password.Substring(0, 24))
        desIV2 = System.Text.Encoding.UTF8.GetBytes(password.Substring(25))
        FileCrypt.DecryptData(fname, fname + "_temp", desKey2, desIV2)
        'avaa avaimet tiedostosta
        Dim fout As New FileStream(fname + "_temp", FileMode.Open, FileAccess.Read)
        fout.Read(desKey, 0, 24)
        fout.Read(desIV, 0, 8)
        fout.Close()
        File.Delete(fname + "_temp")
    End Sub
End Class