I don't know flow of EDIV, Rand.

[J.Kwon]

I'm testing with ANCS example(SDK11.0.0), PCA10028 and Iphone, observing packet with sniffer.

at the first connection,

master sent EDIV(0x0), Rand(0x0), SKDm and IVm to slave. And slave sent SKDs and IVs. And then connection was encypted, slave distribute LTK, EDIV(not 0x0), Rand(not 0x0). And then slave stored EDIV, Rand it sent in m_bond_table[index]

Q1) Should not EVID, Rand master sent be stored in m_bond_table[index] of slave(PCA10028) ??

Q2) why slave sent 12 bytes Rand although BLE_GAP_SEC_RAND_LEN = 7 ?

at the reconnection,

master sent EVID(not 0x0), Rand(not 0x0), SKDm and IVm to slave.

Q3) why does master send non-zero EVID, RAND althouth master does not distribute LTK ??

[run_ar]

Q1: The LL_ENC_REQUEST is sent from the master device, thus these are not relevant unless the devices switch roles in the future. Not supperted by device manager peripheral.
Q2: Rand is a 64 bit number. Not to familiar with the TI sniffer...
Q3. when reconnecting, the previous stored bond informatin is used. EDIV and RAND is used to identify the LTK that was exchanged in the first connection.

[J.Kwon]

Q1 : If so.. why do EVID and Rand slave sent save in m_bond_table[]?

Q3 : If so.. when reconnection, Does the master send back the EVID and Rand received to the slave?

[run_ar]

Q1: The EDIV and RAND sent from the slave to the master during bonding is the EDIV and RAND the master will have to send to the slave when reconnecting to identify the LTK. Q3: Yes. Then the slave uses this to look up/identify the LTK in it's bond table.