diff --git a/include/common/f9.h b/include/common/f9.h
new file mode 100644
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--- /dev/null
+++ b/include/common/f9.h
@@ -0,0 +1,33 @@
+/*--------------------------------------------------------
+ * f9.h
+ *--------------------------------------------------------
+*/
+
+
+/* The code has been referred from
+ * 1.https://www.gsma.com/aboutus/wp-content/uploads/2014/12/uea2uia2d1v21.pdf
+ * 2.https://www.gsma.com/aboutus/wp-content/uploads/2014/12/snow3gspec.pdf
+*/
+
+#ifndef F9_H_
+#define F9_H_
+#include "snow_3g.h"
+
+/* f9.
+ * Input key: 128 bit Integrity Key.
+ * Input count:32-bit Count, Frame dependent input.
+ * Input fresh: 32-bit Random number.
+ * Input dir:1 bit, direction of transmission (in the LSB).
+ * Input data: length number of bits, input bit stream.
+ * Input length: 64 bit Length, i.e., the number of bits to be MAC'd.
+ * Output : 32 bit block used as MAC
+ * Generates 32-bit MAC using UIA2 algorithm as defined in Section 4
+ * of https://www.gsma.com/aboutus/wp-content/uploads/2014/12/snow3gspec.pdf
+ * specs document.
+ */
+
+
+u8* f9( u8* key, u32 count, u32 fresh, u32 dir, u8 *data, u64 length);
+
+#endif
+