Verify the integrity of key state update messages using CRC16-CCITT.

shared/crc16.h

@@ -2,6 +2,9 @@
 #define __CRC16_H__
 
 #include <stdint.h>
+#include <stdbool.h>
+
+#define CRC16_HASH_LENGTH 2 // bytes
 
 typedef struct Crc16Data {
     uint16_t currentCrc;
@@ -22,4 +25,7 @@ void crc16_update(crc16_data_t *crc16Config, const uint8_t *src, uint32_t length
 //! @param hash Pointer to the value returned for the final calculated crc value.
 void crc16_finalize(crc16_data_t *crc16Config, uint16_t *hash);
 
+void CRC16_AppendToMessage(uint8_t *message, uint32_t lengthInBytes);
+bool CRC16_IsMessageValid(uint8_t *message, uint32_t lengthInBytes);
+
 #endif