Crypto: AES CTR

The AES CTR sample shows how to perform AES encryption and decryption operations using the CTR block cipher mode without padding and a 128-bit AES key.

Requirements

The sample supports the following development kits:

Hardware platforms	PCA	Board name	Board target
nRF9161 DK	PCA10153	nrf9161dk	nrf9161dk/nrf9161/ns nrf9161dk/nrf9161
nRF9160 DK	PCA10090	nrf9160dk	nrf9160dk/nrf9160/ns nrf9160dk/nrf9160
nRF9151 DK	PCA10171	nrf9151dk	nrf9151dk/nrf9151/ns nrf9151dk/nrf9151
nRF54L15 PDK	PCA10156	nrf54l15pdk	nrf54l15pdk/nrf54l15/cpuapp
nRF54L15 DK	PCA10156	nrf54l15dk	nrf54l15dk/nrf54l15/cpuapp/ns nrf54l15dk/nrf54l15/cpuapp
nRF54H20 DK	PCA10175	nrf54h20dk	nrf54h20dk/nrf54h20/cpuapp
nRF5340 DK	PCA10095	nrf5340dk	nrf5340dk/nrf5340/cpuapp/ns nrf5340dk/nrf5340/cpuapp
nRF52840 DK	PCA10056	nrf52840dk	nrf52840dk/nrf52840

When built for a board target with the */ns variant, the sample is configured to compile and run as a non-secure application with Cortex-M Security Extensions enabled. Therefore, it automatically includes Trusted Firmware-M that prepares the required peripherals and secure services to be available for the application.

Overview

The sample performs the following operations:

1. Initialization:

   1. The Platform Security Architecture (PSA) API is initialized.

   2. A random AES key is generated and imported into the PSA crypto keystore.

2. Encryption and decryption of a sample plaintext:

   1. A random initialization vector (IV) is generated.

   2. Encryption is performed.

   3. Decryption is performed.

3. Cleanup:

   1. The AES key is removed from the PSA crypto keystore.

Building and running

This sample can be found under samples/crypto/aes_ctr in the nRF Connect SDK folder structure.

When built as firmware image for a board target with the */ns variant, the sample has Cortex-M Security Extensions (CMSE) enabled and separates the firmware between Non-Secure Processing Environment (NSPE) and Secure Processing Environment (SPE). Because of this, it automatically includes the Trusted Firmware-M (TF-M). To read more about CMSE, see Processing environments.

To build the sample, follow the instructions in Building an application for your preferred building environment. See also Programming an application for programming steps and Testing and optimization for general information about testing and debugging in the nRF Connect SDK.

Note

When building repository applications in the SDK repositories, building with sysbuild is enabled by default. If you work with out-of-tree freestanding applications, you need to manually pass the --sysbuild parameter to every build command or configure west to always use it.

Testing

After programming the sample to your development kit, complete the following steps to test it:

1. Connect to the kit with a terminal emulator (for example, nRF Connect Serial Terminal). See Testing and optimization for the required settings and steps.

2. Compile and program the application.

3. Observe the logs from the application using a terminal emulator.