@RosZad This is a peculiarity of CMAC, the other ciphers aren't implemented this way.    I concur with Hanno, \u201cCMAC context\u201d is misleading, the documentation should say \u201cthe cipher context used for the CMAC operation\u201d instead.    This applies to all the parameters `mbedtls_cipher_context_t *ctx` of functions in this module.