Crypto: HMAC

The HMAC sample shows how to generate a message authentication code using the HMAC algorithm and then verify it. The HMAC algorithm in this sample uses SHA-256.

Overview

The sample follows these steps:

1. First, the sample initializes the Platform Security Architecture (PSA) API.

2. Then, it signs and verifies a sample plaintext:

   1. A secret key is generated and imported into the PSA crypto keystore.

   2. HMAC signing is performed.

   3. HMAC verification is performed.

3. Afterwards, it performs cleanup:

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

Requirements

The sample supports the following development kits:

Hardware platforms	PCA	Board name	Build target
nRF5340 DK	PCA10095	nrf5340dk_nrf5340	nrf5340dk_nrf5340_cpuappns
nRF5340 DK	PCA10095	nrf5340dk_nrf5340	nrf5340dk_nrf5340_cpuapp
nRF9160 DK	PCA10090	nrf9160dk_nrf9160	nrf9160dk_nrf9160ns
nRF9160 DK	PCA10090	nrf9160dk_nrf9160	nrf9160dk_nrf9160
nRF52840 DK	PCA10056	nrf52840dk_nrf52840	nrf52840dk_nrf52840

When built for nrf5340dk_nrf5340_cpuappns and nrf9160dk_nrf9160ns targets, the sample is configured to compile and run as a non-secure application. Therefore, it automatically includes TF-M that prepares the required peripherals to be available for the application.

Building and running

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

See Building and programming a sample application for information about how to build and program the application.

Testing

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

1. Connect to the kit with a terminal emulator (for example, PuTTY). See How to connect with PuTTY for the required settings.

2. Compile and program the application.

3. Observe the logs from the application using an RTT Viewer or a terminal emulator.

Note

By default, the sample is configured to use both RTT and UART for logging. If you are using RTT, skip the first step of the testing procedure.