diff --git a/__init__.py b/__init__.py
index f07d8b4..c57d2e9 100755
--- a/__init__.py
+++ b/__init__.py
@@ -87,7 +87,7 @@ def bin(i):
     s = ''.join(str(x) for x in r)
     return s
 
-class bitvector:
+class BitVector:
     def __init__(self, i=0, length=None):
         if type(i) == type(''):
             self._val = 0
diff --git a/crypto.py b/crypto.py
index 32e826b..10df9c6 100644
--- a/crypto.py
+++ b/crypto.py
@@ -214,21 +214,23 @@ def adds(txt):
 
 
 class XorMask:
-    def __init__(self, mask):
+    def __init__(self, mask, stick=False):
         self.offset = 0
         if type(mask) == type(''):
             self._mask = tuple(ord(m) for m in mask)
         else:
             self._mask = tuple(mask)
+        self.stick = stick
 
-    def mask(self, s, stick=False):
+    def __call__(self, s):
         r = []
+        offset = self.offset
         for c in s:
             o = ord(c)
-            r.append(chr(o ^ self._mask[self.offset]))
-            self.offset = (self.offset + 1) % len(self._mask)
-        if not stick:
-            self.offset = 0
+            r.append(chr(o ^ self._mask[offset]))
+            offset = (offset + 1) % len(self._mask)
+        if self.stick:
+            self.offset = offset
         return ''.join(r)