S32K116 - CSEC_DRV_GenerateMAC Calculates Signature Different than other sources

muhammetkalayci — Thu, 02 Feb 2023 08:45:15 GMT

uint8_t plainKey[] = {0xAB, 0xAB, 0xAB, 0xAB, 0xAB, 0xAB, 0xAB, 0xAB,0xAB, 0xAB, 0xAB, 0xAB, 0xAB, 0xAB, 0xAB, 0xAB};

CSEC_DRV_Init(&csecState);
CSEC_DRV_LoadPlainKey(plainKey);

CSEC_DRV_GenerateMAC(CSEC_RAM_KEY, msg, msg_len, cmac, &timeout);

*I use 179 byte message as msg, so msg_len=179.

*16 byte output buffer as cmac.

*timout = 0;

I used same parameters in different libraries to confirm if SDK calculates the right value;

mbedtls calculated a different cmac signature than SDK.

python cryptography library calculated same cmac signature with mbedtls.

a web tool calculated the same signature with mbedtls.

What could be the problem here?

What am I possibly doing wrong?

Re: S32K116 - CSEC_DRV_GenerateMAC Calculates Signature Different than other sources

muhammetkalayci — Thu, 02 Feb 2023 08:46:57 GMT

alright I solved it.

msg_len must be in bits... so in my case it must be 179*8...