diff --git a/left/src/slave_protocol_handler.c b/left/src/slave_protocol_handler.c
index e8719ea..38a47e7 100644
--- a/left/src/slave_protocol_handler.c
+++ b/left/src/slave_protocol_handler.c
@@ -35,6 +35,7 @@ void SlaveProtocolHandler(void)
         case SlaveCommand_GetKeyStates:
             SlaveTxSize = KEY_STATE_BUFFER_SIZE;
             BoolBytesToBits(keyMatrix.keyStates, SlaveTxBuffer, LEFT_KEYBOARD_HALF_KEY_COUNT);
+            CRC16_AppendToMessage(SlaveTxBuffer, KEY_STATE_SIZE);
             break;
         case SlaveCommand_SetTestLed:
             SlaveTxSize = 0;
diff --git a/left/src/slave_protocol_handler.h b/left/src/slave_protocol_handler.h
index d62519f..1ddac7b 100644
--- a/left/src/slave_protocol_handler.h
+++ b/left/src/slave_protocol_handler.h
@@ -4,6 +4,7 @@
 // Includes:
 
     #include "fsl_port.h"
+    #include "crc16.h"
 
 // Macros:
 
@@ -14,7 +15,8 @@
     #define PROTOCOL_RESPONSE_GENERIC_ERROR 1
 
     #define LEFT_KEYBOARD_HALF_KEY_COUNT (KEYBOARD_MATRIX_COLS_NUM*KEYBOARD_MATRIX_ROWS_NUM)
-    #define KEY_STATE_BUFFER_SIZE (LEFT_KEYBOARD_HALF_KEY_COUNT/8 + 1)
+    #define KEY_STATE_SIZE (LEFT_KEYBOARD_HALF_KEY_COUNT/8 + 1)
+    #define KEY_STATE_BUFFER_SIZE (KEY_STATE_SIZE + CRC16_HASH_LENGTH)
 
 // Variables:
 
diff --git a/right/src/slave_drivers/slave_driver_uhk_module.c b/right/src/slave_drivers/slave_driver_uhk_module.c
index 7a83d4e..d869e56 100644
--- a/right/src/slave_drivers/slave_driver_uhk_module.c
+++ b/right/src/slave_drivers/slave_driver_uhk_module.c
@@ -6,6 +6,7 @@
 #include "peripherals/test_led.h"
 #include "test_states.h"
 #include "bool_array_converter.h"
+#include "crc16.h"
 
 uhk_module_state_t UhkModuleStates[UHK_MODULE_MAX_COUNT];
 uhk_module_field_t currentUhkModuleField = UhkModuleField_SendKeystatesRequestCommand;
@@ -38,7 +39,9 @@ void UhkModuleSlaveDriver_Update(uint8_t uhkModuleId)
             currentUhkModuleField = UhkModuleField_SendPwmBrightnessCommand;
             break;
         case UhkModuleField_SendPwmBrightnessCommand:
-            BoolBitsToBytes(rxBuffer, CurrentKeyStates[SLOT_ID_LEFT_KEYBOARD_HALF], LEFT_KEYBOARD_HALF_KEY_COUNT);
+            if (CRC16_IsMessageValid(rxBuffer, KEY_STATE_SIZE)) {
+                BoolBitsToBytes(rxBuffer, CurrentKeyStates[SLOT_ID_LEFT_KEYBOARD_HALF], LEFT_KEYBOARD_HALF_KEY_COUNT);
+            }
             txBuffer[0] = SlaveCommand_SetLedPwmBrightness;
             txBuffer[1] = uhkModuleInternalState->ledPwmBrightness;
             I2cAsyncWrite(I2C_ADDRESS_LEFT_KEYBOARD_HALF, txBuffer, 2);
diff --git a/right/src/slave_drivers/slave_driver_uhk_module.h b/right/src/slave_drivers/slave_driver_uhk_module.h
index 84be347..c94d1f6 100644
--- a/right/src/slave_drivers/slave_driver_uhk_module.h
+++ b/right/src/slave_drivers/slave_driver_uhk_module.h
@@ -4,11 +4,13 @@
 // Includes:
 
     #include "fsl_common.h"
+    #include "crc16.h"
 
 // Macros:
 
     #define UHK_MODULE_MAX_COUNT 1
-    #define KEY_STATE_BUFFER_SIZE (LEFT_KEYBOARD_HALF_KEY_COUNT/8 + 1)
+    #define KEY_STATE_SIZE (LEFT_KEYBOARD_HALF_KEY_COUNT/8 + 1)
+    #define KEY_STATE_BUFFER_SIZE (KEY_STATE_SIZE + CRC16_HASH_LENGTH)
 
 // Typedefs:
 
diff --git a/shared/crc16.c b/shared/crc16.c
index 02dfc25..30027e6 100644
--- a/shared/crc16.c
+++ b/shared/crc16.c
@@ -33,3 +33,24 @@ void crc16_finalize(crc16_data_t *crc16Config, uint16_t *hash)
 {
     *hash = crc16Config->currentCrc;
 }
+
+crc16_data_t crc16data;
+
+void CRC16_AppendToMessage(uint8_t *message, uint32_t lengthInBytes)
+{
+    uint16_t hash;
+    crc16_init(&crc16data);
+    crc16_update(&crc16data, message, lengthInBytes);
+    crc16_finalize(&crc16data, &hash);
+    message[lengthInBytes] = hash & 0xff;
+    message[lengthInBytes+1] = hash >> 8;
+}
+
+bool CRC16_IsMessageValid(uint8_t *message, uint32_t lengthInBytes)
+{
+    uint16_t hash;
+    crc16_init(&crc16data);
+    crc16_update(&crc16data, message, lengthInBytes);
+    crc16_finalize(&crc16data, &hash);
+    return (message[lengthInBytes] == (hash & 0xff)) && (message[lengthInBytes+1] == (hash >> 8));
+}
diff --git a/shared/crc16.h b/shared/crc16.h
index e12fe3c..dc28054 100644
--- a/shared/crc16.h
+++ b/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