Encrypting/decrypting packets on-the-fly

[Hiihtaja]

Hello !

1. Do you have examples for nRF52840 what is demonstrate encryption/decryption packets on the fly as it explained in PS chapter 6.4 ?

2. What about examples for usage of CryptoCell 310 in similar way ? I mean transparently wit some shortcuts from radio to it ?

   It might need if other than default cryptography in use.

Regards,

Eugene

[Einar Thorsrud]

Hi Eugene,

Hiihtaja said:

It is not so clear if after decryption on fly, if original encrypted frame is also stored in scratchpad or any other memory area.

It is available in the OUTPTR location, but no where else. The CCM peripheral does not use RAM for context memory or similar, so there is no other parts of the RAM that holds any data.

Hiihtaja said:

What about encryption on fly ? Does encrypted packet stored in some place after it transferred to air ?

It is also stored in the memory pointed to by OUTPTR.

[Hiihtaja]

Hi Einar !

What about MODE.DATARATE register values. Are all of them are specified ?

Co-processor should perform AES-CCM faster than radio and may be this asynchronous value is not specified.

Looks like co-processor can be used synchronously with Nordic's proprietary and Bluetooth® low energy modes only.

But no any way to attach it to IEEE 802.15.4 radio, at list in some partial way to use it on fly ?

Regards,

Eugene

[Einar Thorsrud]

The CCM peripheral is designed specifically for use with BLE, and only supports data rates relevant for that. So for the nRF52840 you have 1Mbps, 2Mbps, 125 kbps and 500 kbps. No other data rates are possible (so no 250 kbps for 802.15.4).