Improve the default seeding in random module to use 32 bytes of entropy when available.

Lib/random.py

@@ -108,7 +108,7 @@ class Random(_random.Random):
 
         if a is None:
             try:
-                a = long(_hexlify(_urandom(16)), 16)
+                a = long(_hexlify(_urandom(32)), 16)
             except NotImplementedError:
                 import time
                 a = long(time.time() * 256) # use fractional seconds

Misc/NEWS

@@ -44,6 +44,10 @@ Library
   as documented.  The pattern and source keyword parameters are left as
   deprecated aliases.
 
+- Improve the random module's default seeding to use 256 bits of entropy
+  from os.urandom().  This was already done for Python 3, mildly improving
+  security with a bigger seed space.
+
 - Issue #15618: Make turtle.py compatible with 'from __future__ import
   unicode_literals'.  Initial patch by Juancarlo Añez.