diff --git a/Makefile b/Makefile
index 1e6b38b..bbc7983 100644
--- a/Makefile
+++ b/Makefile
@@ -23,6 +23,7 @@ LDFLAGS += $(LIBCBOR)
 CFLAGS = -O2 -fdata-sections -ffunction-sections
 
 INCLUDES = -I./tinycbor/src -I./crypto/sha256 -I./crypto/micro-ecc/ -Icrypto/tiny-AES-c/ -I./fido2/ -I./pc -I./fido2/extensions
+INCLUDES += -I./crypto/cifra/src
 
 CFLAGS += $(INCLUDES)
 # for crypto/tiny-AES-c