AES 256 bit support for RT1062?

[Robert123]

When I am trying to connect and perform a SSL handshake to a HTTPS server, the function "mbedtls_ssl_handshake" return the following error: -0x0023 MBEDTLS_ERR_AES_FEATURE_UNAVAILABLE.

I am able to use the SDK example "eaimxrt1062_lwip_httpscli_mbedTLS_freertos" to create a HTTPS client and connect to the test server which sends a 128 bit AES key. The server I am trying to connect to sends a 256 bit AES key and the function "mbedtls_aes_setkey_enc" in ksdk_mbedtls.c is the origin of the error message:

#ifdef MBEDTLS_AES_ALT_NO_256
    if (keybits == 256u)
    {
        return (MBEDTLS_ERR_AES_FEATURE_UNAVAILABLE);
    }
#endif

Is there any support for AES-256?

I am using a Embedded Artists imx-rt1062-developers-kit with the following 2.9.3 version of the SDK.

[mjbcswitzerland · Accepted solution]

Hi

The mbedtls library includes AES256 as SW implementation in the file aes.c so you should not be missing the support itself.

What happens if you remove the define

MBEDTLS_AES_ALT_NO_256

from the configuration file or the pre-processor defines?

Regards

Mark

[Robert123]

Thanks, I removed the hardware acceleration code in the folder /port and increased the SSL frame buffer (MBEDTLS_SSL_MAX_CONTENT_LEN) in the mbedtls_config_client.h