py3

lib/msqr.py

@@ -1,3 +1,9 @@
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+from __future__ import unicode_literals
+
+import six
 # from http://eli.thegreenplace.net/2009/03/07/computing-modular-square-roots-in-python/
 
 def modular_sqrt(a, p):
@@ -26,7 +32,7 @@ def modular_sqrt(a, p):
     elif p == 2:
         return p
     elif p % 4 == 3:
-        return pow(a, (p + 1) / 4, p)
+        return pow(a, (p + 1) // 4, p)
 
     # Partition p-1 to s * 2^e for an odd s (i.e.
     # reduce all the powers of 2 from p-1)
@@ -34,7 +40,7 @@ def modular_sqrt(a, p):
     s = p - 1
     e = 0
     while s % 2 == 0:
-        s /= 2
+        s //= 2
         e += 1
 
     # Find some 'n' with a legendre symbol n|p = -1.
@@ -59,7 +65,7 @@ def modular_sqrt(a, p):
     # both a and b
     # r is the exponent - decreases with each update
     #
-    x = pow(a, (s + 1) / 2, p)
+    x = pow(a, (s + 1) // 2, p)
     b = pow(a, s, p)
     g = pow(n, s, p)
     r = e
@@ -67,7 +73,7 @@ def modular_sqrt(a, p):
     while True:
         t = b
         m = 0
-        for m in xrange(r):
+        for m in range(r):
             if t == 1:
                 break
             t = pow(t, 2, p)
@@ -90,5 +96,5 @@ def legendre_symbol(a, p):
     Returns 1 if a has a square root modulo
     p, -1 otherwise.
     """
-    ls = pow(a, (p - 1) / 2, p)
+    ls = pow(a, (p - 1) // 2, p)
     return -1 if ls == p - 1 else ls