diff --git a/src/asn1helpers.h b/src/asn1helpers.h
index 17d0d89..cb558da 100644
--- a/src/asn1helpers.h
+++ b/src/asn1helpers.h
@@ -5,8 +5,8 @@
 #include "BIT_STRING.h"
 #include "OCTET_STRING.h"
 
-void asn1_u32_to_bitstring(BIT_STRING_t *bitstr, uint32_t *in);
-void asn1_u24_to_bitstring(BIT_STRING_t *bitstr, uint32_t *in);
+void asn1_u32_to_bitstring(BIT_STRING_t *bitstr, uint32_t *buf, uint32_t in);
+void asn1_u24_to_bitstring(BIT_STRING_t *bitstr, uint32_t *buf, uint32_t in);
 int asn1_strncpy(char *out, const OCTET_STRING_t *in, size_t n);
 uint16_t asn1str_to_u16(const OCTET_STRING_t *in);
 uint8_t asn1str_to_u8(const OCTET_STRING_t *in);