diff --git a/include/common/snow_3g.h b/include/common/snow_3g.h
new file mode 100644
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--- /dev/null
+++ b/include/common/snow_3g.h
@@ -0,0 +1,44 @@
+/*---------------------------------------------------------
+* SNOW_3G.h
+*---------------------------------------------------------*/
+/*
+ * The code has been referred from
+ * 1. https://www.gsma.com/aboutus/wp-content/uploads/2014/12/snow3gspec.pdf
+ * 2. https://www.gsma.com/aboutus/wp-content/uploads/2014/12/uea2uia2d1v21.pdf
+ */
+
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+
+
+typedef unsigned char u8;
+typedef unsigned int u32;
+typedef unsigned long long u64;
+
+/* Initialization.
+ * Input k[4]: Four 32-bit words making up 128-bit key.
+ * Input IV[4]: Four 32-bit words making 128-bit initialization variable.
+ * Output: All the LFSRs and FSM are initialized for key generation.
+ * See Section 4.1 of
+ * (https://www.gsma.com/aboutus/wp-content/uploads/2014/12/snow3gspec.pdf)
+ * specs document.
+ */
+
+
+void Initialize(u32 k[4], u32 IV[4]);
+
+/* Generation of Keystream.
+* input n: number of 32-bit words of keystream.
+* input z: space for the generated keystream, assumes
+* memory is allocated already.
+* output: generated keystream which is filled in z
+* See section 4.2 of
+* (https://www.gsma.com/aboutus/wp-content/uploads/2014/12/snow3gspec.pdf)
+* specs document.
+*/
+
+void GenerateKeystream(u32 n, u32 *z);
+