 Hands-on pairing over pass key entry with display only. Mobile phone indicates that it supports both keyboard and a display. And in this hands-on, WB will indicate during pairing feature exchange that it supports display only. So pass key entry method will be used for pairing. The WB will generate a 6 digit decimal number that we will enter in the phone during the pairing. In the CUPA mix we should change the IO capabilities to display only and in this case we can require protection against man in the middle attack because pass key entry does provide protection against this type of attack. There are two ways to generate this 6 digit decimal number. It can be either static, which means the same number is used for all pairing or it can be dynamically generated and unique for each pairing. When dynamic generation is enabled the BLE stack creates an event towards the user application and the user application is expected to return this 6 digit number. Normally this number would be randomly generated and unique but for simplicity in this example we will hard-code this value into the firmware. In the CUPA mix we will set in the BLE pairing tab not to use a fixed pin and in the application we will process the pass key request that is generated by BLE stack and in return we will send back the pin which in this case will be just 123456. So let's again go to the vpan middleware and let's firstly change the IO capabilities to display only. We can set that we require protection against man in the middle attack and now let's go to the BLE pairing tab. We enable the parameters and set not to use a fixed pin which means the BLE stack will generate events on each and every pairing. Now we can also go to the configuration of our custom service and here instead of to require encryption encrypted link we may also require authenticated link which is a stronger requirement. And this is it, we can regenerate the code and make the small modification in the upper BLE.c. So now we are back in the upper BLE.c and on line 505 there is the event parser for the pass key request and here we should send back the 6 digit decimal number so let's set it to 123456 and we can compile the code and make another test. So as we have done a few times before I will open the STBLE toolbox connect to my device and try to read the characteristic value. So again a pairing message pops up I should enter the hard coded value 123456 and as you see the characteristic value is returned and this is the end of the hands-on.