ENCODER/DÉCODER UN TEXTE AVEC UN RICHTEXTBOX

'///A placer Dans un modules ou Form\\\

Imports System.Security.Cryptography 
Imports System.Text 

'///******* Encrypter le texte *******\\\
Public Function GetEncryptedData(ByVal Data As String) As String
   Dim shaM As New SHA1Managed
   Convert.ToBase64String(shaM.ComputeHash(Encoding.ASCII.GetBytes(Data)))
   Dim eNC_data() As Byte = ASCIIEncoding.ASCII.GetBytes(Data)
   Dim eNC_str As String = Convert.ToBase64String(eNC_data)
   GetEncryptedData = eNC_str
End Function

'///******* Decrypter le texte *******\\\
Public Function GetDecryptedData(ByVal Data As String) As String
   Dim dEC_data() As Byte = Convert.FromBase64String(Data)
   Dim dEC_Str As String = ASCIIEncoding.ASCII.GetString(dEC_data)
   GetDecryptedData = dEC_Str
End Function


'///*********************************\\\


'///**********le tout tien compte de l'utilisation du controle RichTextBox,*********\\\
'///d'un form contenant un menu principal et d'un Module********************\\\

'///********Utilise de cette facon*********\\\

Private Sub mnuFilesOpen_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles mnuFilesOpen.Click

        '///Texte A DecryptER\\\
        rtfNotes.LoadFile(sfile, RichTextBoxStreamType.RichText)

        '///Decrypte Texte\\\
        rtfNotes.Rtf = GetDecryptedData(rtfNotes.Text)
        rtfNotes.SelectionStart = Len(rtfNotes.Text)
End Sub

Private Sub mnuFilesSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles mnuFilesSave.Click
    '///Encrypter Texte\\\
     rtfNotes.Text = GetEncryptedData(rtfNotes.Rtf)
    
    '///Texte a Encrypter\\\
    rtfNotes.SaveFile(sfile, RichTextBoxStreamType.RichText)
    
    '///Decrypter Texte\\\
    rtfNotes.Rtf = GetDecryptedData(rtfNotes.Text)    
    rtfNotes.SelectionStart = Len(rtfNotes.Text)
End Sub