https://devzone.nordicsemi.com/f/nordic-q-a/82319/aes-128-encryption-problem-tom-sHi 1、The customer wants to use AES-128 encryption in their project and want to know how much flash and RAM space does AES-128 encryption use ，I found cifra_AES128-EAX folder in directory nRF5_SDK_17.0.2_d674dde\external\cifra_AES128-EAX of sdk，But Ien-USTelligent Community 13Thu, 02 Dec 2021 08:58:05 GMThttps://devzone.nordicsemi.com/thread/341656?ContentTypeID=1Thu, 02 Dec 2021 08:58:05 GMT137ad170-7792-4731-bb38-c0d22fbe4515:4fc6351c-699a-4d3e-b820-c741fe0a9a8dEinar Thorsrud<p>Hi,</p> <p>The&nbsp;ble_app_hrs does not use AES.128-AEX. I am not entirely sure which variant of AES-128&nbsp;the customer wants to use? Do you know it is AEX? There are several variants, so that is key information. The flash and RAM consumption depends on the algorithm, and which library is used.</p> <p>the nRF5 SDK includes the <a href="https://infocenter.nordicsemi.com/topic/sdk_nrf5_v17.1.0/lib_crypto.html">nrf_crypto library</a>, which is a frontend for many different crypto libraries and is used across the nRF5 SDK wherever crypto is needed. It is not a requirement to use that, but I suggest looking at that first. The documentation there is quite good, and there are a number of examples in the SDK (&lt;SDK&gt;\examples\crypto\nrf_crypto\).</p><div style="clear:both;"></div>