AES Function question

[Hannibalhz]

Dear Nordic engineers

I study the AES examples.I have a question and would like to ask you.

I study the aes_ctr examples.I found that this program use two functions to encrypt the text.

Their is "nrf_crypto_aes_finalize()" and "nrf_crypto_aes_update()".

I read the function's brief of nrf_crypto_aes.h file.I found that nrf_crypto_aes_finalize() 、nrf_crypto_aes_update()、nrf_crypto_aes_crypt（）can encrypt data.

So I would like to know these three function how to use? what's the difference between these there fuctions?

Please answer my question.

Best regards.

[Kazi Afroza Sultana]

Hello,

Here is the documentation of the https://infocenter.nordicsemi.com/topic/sdk_nrf5_v17.1.0/lib_crypto_aes.html?cp=8_1_3_11_15_0  where you can find details of Advanced Encryption Standard.

There are two ways to use the AES related functions API, either by using nrf_crypto_init, nrf_crypto_aes_key_set, nrf_crypto_aes_iv_set (for some ciphers), nrf_crypto_aes_update, nrf_crypto_aes_finalize or though the nrf_crypto_aes_crypt. The latter option does all the operations in a single integrated step. SO, here the step is you have to initialize the context first, then to set the keys and initialization vector and later finalize the aes cryptography. How these functions work are briefly described in the above link. 

I hope it helps.

Thanks.

Best Regards,

Kazi Afroza Sultana