diff --git a/include/osmocore/comp128.h b/include/osmocore/comp128.h
new file mode 100644
index 0000000..c37808f
--- /dev/null
+++ b/include/osmocore/comp128.h
@@ -0,0 +1,22 @@
+/*
+ * COMP128 header
+ *
+ * See comp128.c for details
+ */
+
+#ifndef __COMP128_H__
+#define __COMP128_H__
+
+#include <stdint.h>
+
+/*
+ * Performs the COMP128 algorithm (used as A3/A8)
+ * ki    : uint8_t [16]
+ * srand : uint8_t [16]
+ * sres  : uint8_t [4]
+ * kc    : uint8_t [8]
+ */
+void comp128(uint8_t *ki, uint8_t *srand, uint8_t *sres, uint8_t *kc);
+
+#endif /* __COMP128_H__ */
+