[mbed-tls] Re: Output format of mbedtls_ecdh_make_params does not play well with TLS 1.3

On 9/13/2023 12:28 AM, Gilles Peskine via mbed-tls wrote:

Hi Christian,

Mbed TLS doesn't support the 16-byte variant yet. Currently the initial counter value is always 0 with the PSA API and with the legacy cipher API. https://github.com/Mbed-TLS/mbedtls/issues/5616

You can use a different ICV with the low-level mbedtls_chacha20_xxx API.

Best regards,

Thanks, that's what I did.

I have verified that the PSA API work well for AES 128 and 256, ECB and CTR. I also verified that the APIs in chacha20.h for CHACHA20 work. When the 16-byte variant is supported, I will switch to using the PSA API for CHACHA20 as well.

The PSA API appears to work for all the AEAD variants that I need, including with ChaChaPoly.

-- Christian Huitema