CC2650: Encrypt advertisement packets in hardware

Martin Camenzind

Part Number: CC2650

We use the tirtos_simplelink_2_13_00_06 stack with the simpleBLEBroadcaster.c example and developed a low-power sensor application which works fine. Now we would like to encrypt our advertisement packets with the hardware AES-Modul from the CC2650.

We tried using HCI_LE_EncryptCmd(myKey, myPlainText) in the SimpleBLEBroadcaster_taskFxn() and added an event listener to the GAPRole (broadcaster.c). From there, our callback function myEncryptCb() should be called. Sadly this does not happen. Any suggestions how to proceed?

static void gapRole_processStackMsg(ICall_Hdr *pMsg)
{
  switch (pMsg->event)
  {
    case GAP_MSG_EVENT:
      gapRole_processGAPMsg((gapEventHdr_t *)pMsg);
      break;

    case HCI_SMP_EVENT_EVENT: // TODO: CAM: Added option for AES-Encryption

        if( pMsg->status == HCI_COMMAND_COMPLETE_EVENT_CODE  )
        {
          hciEvt_CmdComplete_t *pPkt = (hciEvt_CmdComplete_t *)pMsg;

          if (pPkt->cmdOpcode == HCI_LE_ENCRYPT)
          {
            extern void myEncryptCb(uint8_t, uint8_t *);
            myEncryptCb(pPkt->pReturnParam[0], &pPkt->pReturnParam[1]);
          }
        }
    break;

    default:
      break;
  }
}

Kind regards

Martin

over 9 years ago

0 Christin Lee over 9 years ago

TI__Guru 56405 points

Hi Martin,

You will need to do the following in order to get the callback from the stack

1. Add the following into the SimpleBLEBroadcaster_init function

// Register with GAP for HCI/Host messages

GAP_RegisterForMsgs(selfEntity);

2. The callback will be sent back to application layer with event type = HCI_GAP_EVENT_EVENT

That means you need to add the following call in to static void SimpleBLEBroadcaster_processStackMsg(ICall_Hdr *pMsg)

    case HCI_GAP_EVENT_EVENT: // TODO: CAM: Added option for AES-Encryption

        if( pMsg->status == HCI_COMMAND_COMPLETE_EVENT_CODE  )
        {
          hciEvt_CmdComplete_t *pPkt = (hciEvt_CmdComplete_t *)pMsg;

          if (pPkt->cmdOpcode == HCI_LE_ENCRYPT)
          {
             asm("NOP");//whatever you want to do here
          }
        }

0 Martin Camenzind over 9 years ago in reply to Christin Lee

Prodigy 50 points

Thank you Christin for your fast reply!

This solution does indeed work! Thanks

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CC2650: Encrypt advertisement packets in hardware