diff --git a/include/big.h b/include/big.h
index c8a60b3..dd950d2 100644
--- a/include/big.h
+++ b/include/big.h
@@ -299,7 +299,7 @@ class Big
               {if (mr_compare(b1.fn,b2.fn)>0) return TRUE; else return FALSE;}
 
     friend Big from_binary(int,char *);
-    friend int to_binary(const Big&,int,char *,BOOL justify=FALSE);
+    friend int to_binary(const Big&,int,char *,BOOL justify/*=FALSE*/);
     friend Big modmult(const Big&,const Big&,const Big&);
     friend Big mad(const Big&,const Big&,const Big&,const Big&,Big&);
     friend Big norm(const Big&);
@@ -321,7 +321,7 @@ class Big
                                                          // x^m.y^k mod n 
     friend Big pow(int,Big *,Big *,Big);  // x[0]^m[0].x[1].m[1]... mod n
 
-    friend Big luc(const Big& ,const Big&, const Big&, Big *b4=NULL);
+    friend Big luc(const Big& ,const Big&, const Big&, Big *b4/*=NULL*/);
 	friend Big moddiv(const Big&,const Big&,const Big&);
     friend Big inverse(const Big&, const Big&);
     friend void multi_inverse(int,Big*,const Big&,Big *);
@@ -353,8 +353,8 @@ class Big
     friend void modulo(const Big&);
     friend BOOL modulo(int,int,int,int,BOOL);
     friend Big get_modulus(void);
-    friend int window(const Big&,int,int*,int*,int window_size=5);
-    friend int naf_window(const Big&,const Big&,int,int*,int*,int store=11);
+    friend int window(const Big&,int,int*,int*,int window_size/*=5*/);
+    friend int naf_window(const Big&,const Big&,int,int*,int*,int store/*=11*/);
     friend void jsf(const Big&,const Big&,Big&,Big&,Big&,Big&);
 
 /* Montgomery stuff */
diff --git a/include/zzn.h b/include/zzn.h
index b5f55b8..7c4d08e 100644
--- a/include/zzn.h
+++ b/include/zzn.h
@@ -183,7 +183,7 @@ class ZZn
     friend ZZn getB(void);        // get B parameter of elliptic curve
 
     friend ZZn  sqrt(const ZZn&); // only works if modulus is prime
-    friend ZZn  luc( const ZZn&, const Big&, ZZn* b3=NULL);
+    friend ZZn  luc( const ZZn&, const Big&, ZZn* b3/*=NULL*/);
 
     big getzzn(void) const;
 
diff --git a/source/zzn.cpp b/source/zzn.cpp
index e39c5de..0a209e6 100644
--- a/source/zzn.cpp
+++ b/source/zzn.cpp
@@ -167,7 +167,7 @@ ZZn pow(int n,ZZn *a,Big *b)
 
 ZZn powl(const ZZn& x,const Big& k)
 {
-    return luc(2*x,k)/2;
+    return luc(2*x,k, NULL)/2;
 }
 
 ZZn luc( const ZZn& b1, const Big& b2, ZZn *b3)