diff --git a/IDEA.py b/IDEA.py
index c58746dfafa364fdc0f7e02843a4a40fe391f5d1..125e4fa6d0177b0e80cdf413d170ebd50b77adf1 100644
--- a/IDEA.py
+++ b/IDEA.py
@@ -31,6 +31,12 @@ def Invert_Mod(a):
     else : 
         return Fast_exp(a, m - 2, m)
 
+def gcd(a,b):
+    if (b==0):
+        return a
+    else:
+        return gcd(b, a % b)
+
 def Fast_exp(b, e, m):
     '''
     Function of fast exponation
@@ -66,12 +72,6 @@ def Split_str(s, p): #Split a string
 def Shift(k):
     return k[6:] + k[0:6]
 
-def gcd(a,b):
-    if (b==0):
-        return a
-    else:
-        return gcd(b, a % b)
-
 def Round(lst_msg,lst_k):
     step1 = Mult_mod(lst_msg[0],lst_k[0])
     step2 = Add_mod(lst_msg[1],lst_k[1])