diff --git a/crypto/Makefile b/crypto/Makefile
index 99cc64a..bd6a029 100644
--- a/crypto/Makefile
+++ b/crypto/Makefile
@@ -40,6 +40,7 @@
 
 $(obj)/rsapubkey-asn1.o: $(obj)/rsapubkey-asn1.c $(obj)/rsapubkey-asn1.h
 $(obj)/rsaprivkey-asn1.o: $(obj)/rsaprivkey-asn1.c $(obj)/rsaprivkey-asn1.h
+$(obj)/rsa_helper.o: $(obj)/rsapubkey-asn1.h $(obj)/rsaprivkey-asn1.h
 clean-files += rsapubkey-asn1.c rsapubkey-asn1.h
 clean-files += rsaprivkey-asn1.c rsaprivkey-asn1.h