diff --git a/src/iu_helpers.h b/src/iu_helpers.h
new file mode 100644
index 0000000..4733bbc
--- /dev/null
+++ b/src/iu_helpers.h
@@ -0,0 +1,6 @@
+#pragma once
+
+#include <stdint.h>
+
+int decode_iu_bcd(char *out, size_t out_len, const uint8_t *in, size_t in_len);
+int encode_iu_imsi(uint8_t *out, size_t out_len, const char *in);