B4J Question .net code to B4J

Public Class AES
 
    Dim cAES As RijndaelManaged
 
    Public Sub New(ByVal AESkey As Byte())
 
        Dim InitVector() As Byte = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
 
        cAES = New RijndaelManaged
        cAES.BlockSize = 128
        cAES.KeySize = 128
        cAES.Mode = CipherMode.ECB
        cAES.IV = InitVector
        cAES.Padding = PaddingMode.Zeros
        cAES.Key = AESkey
 
    End Sub
 
    Public Sub Decrypt(ByRef cBytes As Byte(), ByVal NumBytes As Integer)
 
        Dim PlainBytes(IOBuffSize) As Byte
        Dim i As Integer
 
        Dim cDecryptor As ICryptoTransform = cAES.CreateDecryptor()
 
        ' Skip over the first 13 bytes - they are already in the plain.
        For i = 13 To NumBytes - 16 Step 16
            cDecryptor.TransformBlock(cBytes, i, 16, PlainBytes, i)
        Next
        Array.Copy(PlainBytes, 13, cBytes, 13, NumBytes - 13)
 
    End Sub
 
    Public Sub Encrypt(ByRef cBytes As Byte(), ByRef NumBytes As Integer)
 
        Dim EncryptedBytes(IOBuffSize) As Byte
        Dim i As Integer
 
        ' pad to a multiple of 16
        Dim numPadBytes As Integer = 16 - ((NumBytes - 13) Mod 16)
        ReDim Preserve cBytes(NumBytes + numPadBytes - 1)
        For i = NumBytes To NumBytes + numPadBytes - 1
            cBytes(i) = 0
        Next i
        NumBytes += numPadBytes
 
        Dim cEncryptor As ICryptoTransform = cAES.CreateEncryptor()
 
        ' Skip over the first 13 bytes - they are left in the plain.
        For i = 13 To NumBytes - 1 Step 16
            cEncryptor.TransformBlock(cBytes, i, 16, EncryptedBytes, i)
        Next
        Array.Copy(EncryptedBytes, 13, cBytes, 13, NumBytes - 13)
 
    End Sub
 
End Class

Private Sub RMSockUDP_PacketArrived (Packet As UDPPacket)
    Decrypt(Packet.Data)
End Sub

Sub Decrypt(value() As Byte) As String
    Try
        Dim raw() As Byte = value
        bb.Initialize
        bb.Append(raw)
        Dim binaryflag() As Byte = Array As Byte(0x33, 0x36, 0x37, 0x30, 0x42, 0x42, 0x39, 0x46, 0x2f,0x2f,0x31,0x2f,0x2f)
        If bb.IndexOf(binaryflag) > -1 Then
            Dim msgbytes() As Byte = bb.SubArray2(13,bb.IndexOf2(Array As Byte(0x0),13))
        End If

        kg.Initialize("AES")
        kg.KeyFromBytes("0123456789ABCDEF".GetBytes("UTF8")) ' the key to encrypt the message was 0123456789ABCDEF
        C.Initialize("AES/ECB/NoPadding")
        msgbytes = C.Decrypt(msgbytes, kg.Key, False)
        
        Return BConv.StringFromBytes(msgbytes, "UTF8").Trim
    Catch
        Log("Error: " & LastException.message)
    End Try
End Sub