Encrypting packets on-the-fly when MODE.LENGTH = Extended

RE: Encrypting packets on-the-fly when MODE.LENGTH = Extended

Hiihtaja — Wed, 16 Feb 2022 09:23:49 GMT

Hi !

There I found some exact settings of MAXPACKET size :

Should MAXPACKET size be so exact in case of RX/TX ?

Can I set to max value 251 always ?

Or it have some effect for encrypt/decrypt process ?

I think only LENGTH of packet is in use.

Regards,

Eugene

Sigurd — Wed, 16 Feb 2022 08:51:22 GMT

Hi,

Maybe it would be helpful to take a look at how it's done in the Zephyr Bluetooth Controller.

Hiihtaja — Tue, 15 Feb 2022 18:19:41 GMT

Hi !

Looks like in case of decryption, the same channel should be used and no need nothing else

if NRF_CCM->TASKS_KSGEN = 1; is enabled beforehand

NRF_PPI->CHEN |= (1UL << NRF_PPI_CHANNEL25);

Is this so ?

Can KSGEN be triggered even before than TASKS_TXEN/RXEN tasks ?

Or better to start it synchronously with TXEN/RXEN ? Or attach to other radio events ?

I have done KSGEN beforehand but looks like something wrong and encrypted data are not decrypted properly on RX side.

What about RFU byte ( S1) ? Looks like if on-fly mode is enabled, it must be present.

S1LEN and S1INC in PCFN0 should be > 0

Is this so ?

Regards,

Eugene

Sigurd — Tue, 15 Feb 2022 14:26:30 GMT

Hi,

[quote user=""]RADIO->EVENTS_ADDRESS -> CCM->TASKS_CRYPT ?[/quote]