License Key for My App

[FabioG]

Hello to all,

I need to include in my application a license key
the user at first launch of the app needs to display a message with a code
which will be used to generate the key to unlock the application.

Do you have any suggestions?

thank you very much
Fabio

 

[FabioG]

I wrote a very simple code

on the pc I wrote a program in vb.net to generate the key.

This should prevent a bit to my private clients to spread the application (for applications that do not insert in Google Play)

I understand that the key is generated in a very simple
but I have no other ideas.

Do you have suggestions?

thanks
Fabio

Sub Activity_Create(FirstTime As Boolean)

    If CheckLicense = False Then Activity.Finish

End Sub


Sub CheckLicense As Boolean
   
   Dim InputBox As InputDialog
   
   Dim PhID As String
   Dim ph As PhoneId
   PhID = ph.GetDeviceId
   Dim KeySaved As String
   Dim Key As StringBuilder
   Key.Initialize
      For i = 0 To PhID.Length -1
         Key.Append(KeyGen(PhID.SubString2(i,i+1)))
      Next
   
   If File.Exists(File.DirInternal, "License.dat") Then
      Rf.Initialize(File.DirInternal,"License.dat",True)   
      KeySaved = Rf.ReadObject(Rf.CurrentPosition)
      Rf.Close
      If KeySaved = Key.ToString Then Return True      
      If KeySaved <> Key.ToString Then
         InputBox.InputType = InputBox.INPUT_TYPE_TEXT
         InputBox.PasswordMode = False
         InputBox.Show("Insert License Key","License Key","OK","Cancel","",Null)   
         If InputBox.Response = -3 Then Return False
         If InputBox.Response = -1 Then
            If Key.ToString = InputBox.Input Then
               KeySaved = InputBox.Input
               Rf.Initialize(File.DirInternal,"License.dat",False)
               Rf.WriteObject(KeySaved,False,Rf.CurrentPosition)               
               Rf.Close
               Return True
            End If
         End If
      End If
   Else
      InputBox.InputType = InputBox.INPUT_TYPE_TEXT
      InputBox.PasswordMode = False
      InputBox.Show("Insert License Key","License Key","OK","Cancel","",Null)   
      If InputBox.Response = -3 Then Return False
      If InputBox.Response = -1 Then
         If Key.ToString = InputBox.Input Then
            KeySaved = InputBox.Input
            Rf.Initialize(File.DirInternal,"License.dat",False)
            Rf.WriteObject(KeySaved,False,Rf.CurrentPosition)               
            Rf.Close
            Return True
         End If
      End If
   End If

End Sub
Sub KeyGen(PartKey As String) As String
   
   PartKey = PartKey.ToUpperCase
   
   Select Case PartKey
      Case "0"
         Return "AL"
      Case "1"
         Return "BH"
      Case "2"
         Return "CF"
      Case "3"
         Return "DE"
      Case "4"
         Return "ED"
      Case "5"
         Return "FC"
      Case "6"
         Return "GB"
      Case "7"
         Return "HA"
      Case "8"
         Return "IM"
      Case "9"
         Return "LN"
         
      Case "A"
         Return "0"
      Case "B"
         Return "1"
      Case "C"
         Return "2"
      Case "D"
         Return "3"
      Case "E"
         Return "4"
      Case "F"
         Return "5"
      Case "G"
         Return "6"
      Case "H"
         Return "7"
      Case "I"
         Return "8"
      Case "J"
         Return "9"
      Case "Y"
         Return "10"
      Case "K"
         Return "11"
      Case "L"
         Return "12"
      Case "M"
         Return "13"
      Case "N"
         Return "14"
      Case "O"
         Return "15"
      Case "P"
         Return "16"
      Case "Q"
         Return "17"
      Case "R"
         Return "18"
      Case "S"
         Return "19"
      Case "T"
         Return "20"
      Case "U"
         Return "21"
      Case "V"
         Return "22"
      Case "Z"
         Return "23"
   End Select
End Sub