AES128 Encryption Library

Question

I am using my nRF52833 chip to send 20 bytes beacons frequently. 
 I want to encrypt the initial 16bits of my data using AES128. 
 What is the library to use for this purpose? How to include the initialization vector and encryption key? 
 Thanks

Vidar Berg · Accepted Answer

They all use the AES cipher; the difference is in what mode of operation they support. I think this wiki article explains the differences pretty well: https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation 
 SDK documentation: AES Example

Vidar Berg · Answer

The impact of encryption on your average current consumption will depend on how long it takes to encrypt the payload and how frequently you update the data. I don't think there will be a very noticeable difference, but this is something you have to verify with your application.

Vidar Berg · Answer

The CPU frequency is 64 MHz, but the processing speed does not scale linearly with that. Desktop CPUs have different instruction sets, and most, if not all, come with HW accelerated AES support - similar to how we have dedicated AES peripherals encrypting Bluetooth connections on our chips. The processing time will also depend on how optimized the AES library is. 
 The most accurate way to determine the additional power usage in your case is to actually measure it on the device with a Power Profiler Kit II or similar tool. Alternatively, you can time the AES execution time with a TIMER or the CPU cycle counter and multiply that by the typical CPU current.

AES128 Encryption Library

Top Replies