6.3.2.3 Crypto_Mac_AesCmac_Final

crypto_Mac_Status_E Crypto_Mac_AesCmac_Final(
    st_Crypto_Mac_Aes_ctx *ptr_aesCmacCtx_st, 
    uint8_t *ptr_outMac, 
    uint32_t macLen
    );

Description

This API calculates the MAC using AES-CMAC. To use it, first initialize the context by calling the Crypto_Mac_AesCmac_Init function. Then, call Crypto_Mac_AesCmac_Cipher to calculate the MAC. Once this is done, the API can be called. To verify the MAC, users can compare the generated MAC with the one received from the sender along with the message.

Parameters


No.	Argument Type	Argument Name	Type	Description
1	st_Crypto_Mac_Aes_ctx*	ptr_aesCmacCtx_st	Input	AES-CMAC algorithm context
2	uint8_t*	ptr_outMac	Output	Pointer for MAC
3	uint8_t*	macLen	Input	MAC length in bytes, 16 bytes

Returns


Return Type	Description
crypto_Mac_Status_E	Function returns the status of the API.

Prerequisites

To use the HW handler, the algorithm must be enabled in Crypto v4 in MPLAB® Code Configurator.
To use the SW handler, the algorithm must be enabled in wolfCrypt, and linked to Crypto V4 in MPLAB® Code Configurator.
Crypto_Mac_AesCmac_Init and Crypto_Mac_AesCmac_Update must be called before calling Crypto_Mac_AesCmac_Final.

Example

#define sessionID 1
crypto_Mac_Status_E status;
crypto_HandlerType_E handlerType_en = CRYPTO_HANDLER_SW_WOLFCRYPT;
st_Crypto_Mac_Aes_ctx Mac_Ctx;
uint8_t inputData[32] = {/*data*/};
uint32_t dataLen = sizeof(inputData);
uint8_t key[32] = {/*data*/};
uint32_t keyLen = sizeof(key);
uint8_t mac[16];
uint32_t macLen = 16;

status = Crypto_Mac_AesCmac_Init(
    &Mac_Ctx, 
    handlerType_en, 
    key, 
    keyLen, 
    sessionID
    );

status = Crypto_Mac_AesCmac_Cipher(
    &Mac_Ctx, 
    inputData, 
    dataLen
    );

status = Crypto_Mac_AesCmac_Final(
    &Mac_Ctx, 
    mac, 
    macLen
    );