diff --git a/src/pyj/aes.pyj b/src/pyj/aes.pyj
index d52fae0d40..adc8f77c61 100644
--- a/src/pyj/aes.pyj
+++ b/src/pyj/aes.pyj
@@ -310,17 +310,16 @@ class CBC(ModeOfOperation):
 class Counter:
 
     def __init__(self, initial_value, number_of_bytes=16):
-        self.number_of_bytes = number_of_bytes
-        self.bytes = Uint8Array(number_of_bytes)
         initial_value = initial_value or 1
         if type(initial_value) is 'number':
+            self.bytes = Uint8Array(number_of_bytes)
             self.set_value(initial_value)
         else:
-            self.bytes.set(initial_value)
+            self.bytes = Uint8Array(initial_value)
 
     def set_value(self, value):
         c = self.bytes
-        for v'var index = self.number_of_bytes; index >= 0; index--':
+        for v'var index = self.bytes.length; index >= 0; index--':
             c[index] = value % 256
             value >>= 8
 
@@ -329,7 +328,7 @@ class Counter:
 
     def increment(self):
         c = self.bytes
-        for v'var i = self.number_of_bytes; i >= 0; i--':
+        for v'var i = self.bytes.length; i >= 0; i--':
             if c[i] is 255:
                 c[i] = 0
             else:
@@ -348,9 +347,8 @@ class CTR(ModeOfOperation):
 
     def __init__(self, key, counter):
         ModeOfOperation.__init__(self, key)
-        self.cval = counter
         self.wmem = Uint8Array(16)
-        self.counter = Counter(self.cval)
+        self.counter = Counter(counter)
         self.counter_index = 16
 
     def _crypt(self, bytes):
@@ -399,6 +397,7 @@ class CTR(ModeOfOperation):
             offset = tag_bytes.length
         return bytes_to_string(b, offset)
 
+
 if __name__ == '__main__':
     text = 'testing a basic roundtrip ø̄ū'