Question about BLE encryption / sniffing

[MANGO]

Hi, I use

nRF51822 Rev.3, SDK 7.2, SDK 10.0, S110 8.0, and S120 2.1 most of the time.

I mostly quote most of the codes from the SDK's examples such as HID keyboard or NUS.

I noticed that the advertising packets and NUS data (after pairing is done) packets

could be sniffed as a plain text. (I use the nRF dongle and nRF Sniffer to check it.)

For instance, the nRF Sniffer showed the NUS packets from the peripheral.

So I was wondering if I can encrypt the packets using Nordic's SDK.

As far as I know, the nRF51822 has a AES ECB (Electronic Codebook mode encryption, a single 128 bit AES block encrypt hardware module).

How I can encrypt my data (NUS or HID packets) and advertising packets? I don't want these packets to be revealed as a plain text from sniffers.

I'm hoping for a level of security

which can prevent MITM (Man-in-the-middle attack) and replay attack (playback attack).

Can this be achieved? I expect the answer might depend whether I use bonding or pairing.

// Added at March, 9, 2016

I use the nRF Sniffer at and Wireshark at Windows 10, 32 bit.

-Best Regards, Mango

[RK]

Just make the characteristic require security as is done in dozens of the examples in the SDK. Pairing or bonding will be required, the packets will be encrypted. If you want to have MITM protection then ensure you require Security Mode = 1 and Level = 3.

It's exactly 2 minutes work