diff --git a/cmake/kconfig.cmake b/cmake/kconfig.cmake
index ca09dad150..0d48fab43c 100644
--- a/cmake/kconfig.cmake
+++ b/cmake/kconfig.cmake
@@ -293,6 +293,7 @@ if(EXISTS ${BOARD_DEFCONFIG})
 
 	if(CRYPTO)
 		set(PX4_CRYPTO ${CRYPTO} CACHE STRING "PX4 crypto implementation" FORCE)
+		add_definitions(-DPX4_CRYPTO)
 	endif()
 
 	if(KEYSTORE)