diff --git a/galois.py b/galois.py
index 9750694..73f09ab 100755
--- a/galois.py
+++ b/galois.py
@@ -46,6 +46,16 @@ class GaloisNumber:
             raise ValueError ("Value {0} is outside field".format (v))
         self.value = v
 
+    def mul_region (self, arr, init_value = None):
+        if not init_value:
+            init_value = [GaloisNumber (0, self.field)] * len (arr)
+        if any ([type(x) != GaloisNumber or type(x.field) != type(self.field) for x in arr]):
+            raise ValueError ("All items must be Galois numbers in this field!")
+        return [x * self + i for x, i in zip (arr, init_value)]
+
+    def copy (self):
+        return GaloisNumber (self.value, self.field)
+
     def __add__ (self, other):
         if self.field != other.field:
             raise GaloisException ("Field elements from different fields")
@@ -54,13 +64,13 @@ class GaloisNumber:
     def __iadd__ (self, other):
         if self.field != other.field:
             raise GaloisException ("Field elements from different fields")
-        self.value ^= other.value
+        return self + other
 
     def __sub__ (self, other):
         return self + other
 
     def __isub__ (self, other):
-        self += other
+        return self + other
 
     def __invert__ (self):
         return self.field.invert (self)
@@ -76,7 +86,7 @@ class GaloisNumber:
     def __imul__ (self, other):
         if self.field != other.field:
             raise GaloisException ("Field elements from different fields")
-        self.value = self.field.direct_multiply (self.value, other.value)
+        return self.field.multiply (self, other)
 
     def __floordiv__ (self, other):
         if self.field != other.field:
@@ -94,6 +104,9 @@ class GaloisNumber:
     def __repr__ (self):
         return self.field.fmt (self.value)
 
+    def to_bytes (self):
+        return (self.value).to_bytes ((self.field.bits + 7) // 8, byteorder='big')
+
 class GaloisFieldLog:
     '''
     Pure python implementation of Galois (finite) field arithmetic routines using log/antilog