Arm Mbed OS support forum

CMAC with CBC 128/192/256

I see only CMAC w. ECB modes are supported.
Are there any plans to add CBC modes support for CMAC?

Best regards
Leonid Rosin

Hi @aryeh
Thank you for your query.
I am not sure what is your request.
CMAC is a MAC algorithm that uses a 128 bit block algorithmj, such as AES.
It doesn’t have a mode for CBC or ECB.
It uses the ECB mode, as ECB mode on an input of block size, is equivalent as doing the operation itself on the block.

If you are refering to CBC-MAC, then it is an entirely different algorithm. In this case, you can write your own wrapper code, that will call CBC function, and get the last block of the output as the MAC.

Mbed TLS Team member