B4R Code Snippet Arduino NANO Serial AES-128KeyGen


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Hello guys,

I would like to show you my little project that i ported in B4R and B4J (from Arduino IDE and .NET framework).
As you know Arduino boards can be used for countless activities; in my case i use the NANO board as keygen for a software that i'm coding.

The NANO can store any values you need in the EEPROM, i use just 16 bytes for AES128 encription key.
Remember that the EEPROMs have limited life, so do not call EEPROM.Write inside a While(true) :p

The data stored inside the board is accessible with jSerial library
In this B4J application AES128 isn't coded. it just read the key.


In the example the Arduino board can handle two commands via serial.
  • CMD_GENERATE_KEYS : NANO stores a random 16 bytes array to the EEPROM.
  • CMD_READ_KEYS : NANO read the 16 bytes from the EEPROM and write them to the serial
The software in B4J is a jSerial implementation that allow to send and receive the data with the Arduino.

In order to let this work:
Connect Arduino BOARD (install driver if needed) to an USB
Start the b4j software and connect the COM port.
Read or Write the key.

Here the HOT things, the codes:

B4R Arduino CODE:
Sub Process_Globals
    Public Serial1 As Serial
    Private Astream As AsyncStreams
    Private eeprom As EEPROM
    Dim boardLed As Pin
    Private rndKeys(16) As Byte
    Private CMD_GENERATE_KEYS As Byte = 0x1A
    Private CMD_READ_KEYS As Byte = 0x1B
End Sub

Private Sub AppStart
    Astream.Initialize(Serial1.Stream, "Astream_NewData", "Astream_Error")
    'Init board led
    boardLed.Initialize(13, boardLed.MODE_OUTPUT)
End Sub

Sub Astream_NewData(buffer() As Byte)
    'Led ON for stream operation
    If buffer.Length > 0 Then
        If buffer(0) = CMD_GENERATE_KEYS Then
            sendCommand(CMD_GENERATE_KEYS, Array As Byte(0))
        Else If buffer(0) = CMD_READ_KEYS Then
            Dim tmpKeys(16) As Byte
            eeprom.ReadBytes2(0, 16, tmpKeys)
            sendCommand(CMD_READ_KEYS, tmpKeys)
        End If
    End If
    'Led OFF for idle
End Sub

private Sub sendCommand(cmd As Byte, values() As Byte)
    'Prepare buffer to send
    Dim ary2Send(values.Length + 1) As Byte
    ary2Send(0) = cmd
    For i=0 To values.Length-1
        ary2Send(i+1) = values(i)
    'Send command to serial
End Sub

Sub Astream_Error
End Sub

private Sub GenerateRandomKeys
    'Get seed from microseconds and generate random AES128 key
    For i=0 To 16-1
        rndKeys(i) = Rnd(0, 256)
    'Store keys in eeprom
    eeprom.WriteBytes(rndKeys, 0)
End Sub
B4J App Code:
Sub Process_Globals
    Private fx As JFX
    Private MainForm As Form
    Private ComboBox As ComboBox
    Private TextAreaInfo As TextArea
    Private SerialManager As Serial
    Private aStream As AsyncStreams
    Private aesKey(16) As Byte
    Private BtGenerateKeys As Button
    Private BtReadKeys As Button
    Private const CMD_GENERATE_KEYS As Byte = 0x1A
    Private const CMD_READ_KEYS As Byte = 0x1B
End Sub

Sub AppStart (Form1 As Form, Args() As String)
    MainForm = Form1
    MainForm.RootPane.LoadLayout("Layout1") 'Load the layout file.

End Sub

Private Sub loadPorts
    ComboBox.SelectedIndex = -1
End Sub

#region "Form controls"
Sub BtRefresh_Click
End Sub

Sub ComboBox_SelectedIndexChanged(Index As Int, Value As Object)
    If Index = -1 Then Return
    If Index >= SerialManager.ListPorts.Size Then Return
End Sub

Sub AddTextLine(text As String)
    TextAreaInfo.text = text & CRLF & TextAreaInfo.text
End Sub

Sub BtGenerateKeys_Click
    AddTextLine("Generate new key request")
End Sub

Sub BtReadKeys_Click
    AddTextLine("Key request")
End Sub

#end region

#region "Serial manager"

Sub ConnectSerial(port As String)
    AddTextLine("Connection to: " & port)
    'SerialManager.SetParams(SerialManager.BAUDRATE_38400, SerialManager.DATABITS_8, SerialManager.STOPBITS_1, SerialManager.PARITY_NONE)
    SerialManager.SetParams(SerialManager.BAUDRATE_38400, 8, 1, 0)
    aStream.Initialize(SerialManager.GetInputStream, SerialManager.GetOutputStream, "aStream")
End Sub

private Sub SendCommandToSerial(command As Byte)
    If aStream.IsInitialized Then
        aStream.Write(Array As Byte(command))
        Dim hexStr As String = Bit.ToHexString(command).ToUpperCase
        hexStr = hexStr.SubString(hexStr.Length -2)
    End If
End Sub

Sub AStream_NewData (Buffer() As Byte)
    If Buffer.Length = 0 Then Return
    If Buffer(0) = CMD_GENERATE_KEYS Then
        AddTextLine("Keys generated. Ask for new keys")
        'Keys generated: send read command
    else if Buffer(0) = CMD_READ_KEYS Then
        Dim str As String = "0x"
        For i=0 To 16-1
            'Add key values
            aesKey(i) = Buffer(i+1)
            str = str & Bit.ToHexString(aesKey(i)).ToUpperCase.Replace("FFFFFF", "")
        AddTextLine("Received Keys: " & str)
        'Received data not handled
    End If

End Sub

Sub AStream_Error
    Log("Error: " & LastException)
    AddTextLine("Connection error: " & LastException)
End Sub

Sub AStream_Terminated
    Log("Connection is broken.")
    AddTextLine("Connection broken")
End Sub

#end region
Feel free to leave any comment.
Best regards