diff --git a/include/drivers/st/stm32_hash.h b/include/drivers/st/stm32_hash.h
index 969d7aa..df04730 100644
--- a/include/drivers/st/stm32_hash.h
+++ b/include/drivers/st/stm32_hash.h
@@ -14,7 +14,7 @@
 	HASH_SHA256
 };
 
-int stm32_hash_update(const uint8_t *buffer, uint32_t length);
+int stm32_hash_update(const uint8_t *buffer, size_t length);
 int stm32_hash_final(uint8_t *digest);
 int stm32_hash_final_update(const uint8_t *buffer, uint32_t buf_length,
 			    uint8_t *digest);