ToBase64 / FromBase64

<Extension()> _
Public Function ToBase64(ByVal value As String) As String
    If String.IsNullOrEmpty(value) Then
        Return value
    Else
        Dim encoding As New System.Text.ASCIIEncoding()
        Return Convert.ToBase64String(encoding.GetBytes(value))
    End If
End Function

<Extension()> _
Public Function FromBase64(ByVal value As String) As String
    If String.IsNullOrEmpty(value) Then
        Return value
    Else
        Dim encoding As New System.Text.ASCIIEncoding()
        Return encoding.GetString(Convert.FromBase64String(value))
    End If
End Function

Textbox1.Text.ToBase64

db.Password.FromBase64