lt_ex_macandd()

int lt_ex_macandd

(

lt_handle_t *

h

)

Value MACANDD_ROUNDS represents a number of possible PIN gueses, this value also affects size of lt_macandd_nvm_t struct. Technically TROPIC01 is capable to have this set to 128, therefore provide 128 Mac And Destroy tries, which would require roughly 128*32 bytes in non volatile memory for storing data related to M&D tries.

In this example, TROPIC01's User R-Memory is used as a storage for data during power cycle (specifically, the last slot is used). For a sake of simplicity, only one User R-Memory slot is used as a storage.

Therefore MACANDD_ROUNDS is here limited to 12 -> the biggest possible number of tries which fits into one User R-Memory slot (slot size in User R-Memory is atleast 444B in all TROPIC01 chips).

Note

We recommend reading TROPIC01's datasheet before diving into this example!

Parameters

h

Handle for communication with TROPIC01. It is assumed that the h.l2.device and h.l3.crypto_ctx members were already initialized. Because these members are pointers, the assigned structures must exist throughout the whole life-cycle of the handle. Refer to the 'Get Started'->'Integrating Libtropic'->'How to Use' Section in the Libtropic documentation for more information.

Return values

0	Function executed successfully
-1	Function did not execute successfully